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📁 ..	-	2026-03-21 15:45
📄 __init__.py # mssql/__init__.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php from . import adodbapi # noqa from . import base # noqa from . import mxodbc # noqa from . import pymssql # noqa from . import pyodbc # noqa from . import zxjdbc # noqa from .base import BIGINT from .base import BINARY from .base import BIT from .base import CHAR from .base import DATE from .base import DATETIME from .base import DATETIME2 from .base import DATETIMEOFFSET from .base import DECIMAL from .base import FLOAT from .base import IMAGE from .base import INTEGER from .base import MONEY from .base import NCHAR from .base import NTEXT from .base import NUMERIC from .base import NVARCHAR from .base import REAL from .base import ROWVERSION from .base import SMALLDATETIME from .base import SMALLINT from .base import SMALLMONEY from .base import SQL_VARIANT from .base import TEXT from .base import TIME from .base import TIMESTAMP from .base import TINYINT from .base import try_cast from .base import UNIQUEIDENTIFIER from .base import VARBINARY from .base import VARCHAR from .base import XML base.dialect = dialect = pyodbc.dialect __all__ = ( "INTEGER", "BIGINT", "SMALLINT", "TINYINT", "VARCHAR", "NVARCHAR", "CHAR", "NCHAR", "TEXT", "NTEXT", "DECIMAL", "NUMERIC", "FLOAT", "DATETIME", "DATETIME2", "DATETIMEOFFSET", "DATE", "TIME", "SMALLDATETIME", "BINARY", "VARBINARY", "BIT", "REAL", "IMAGE", "TIMESTAMP", "ROWVERSION", "MONEY", "SMALLMONEY", "UNIQUEIDENTIFIER", "SQL_VARIANT", "XML", "dialect", "try_cast", )	1.77 KB	2026-01-20 12:58
📁 __pycache__	-	2026-03-21 15:45
📄 adodbapi.py # mssql/adodbapi.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """ .. dialect:: mssql+adodbapi :name: adodbapi :dbapi: adodbapi :connectstring: mssql+adodbapi://<username>:<password>@<dsnname> :url: http://adodbapi.sourceforge.net/ .. note:: The adodbapi dialect is not implemented in SQLAlchemy versions 0.6 and above at this time. """ import datetime import sys from sqlalchemy import types as sqltypes from sqlalchemy import util from sqlalchemy.dialects.mssql.base import MSDateTime from sqlalchemy.dialects.mssql.base import MSDialect class MSDateTime_adodbapi(MSDateTime): def result_processor(self, dialect, coltype): def process(value): # adodbapi will return datetimes with empty time # values as datetime.date() objects. # Promote them back to full datetime.datetime() if type(value) is datetime.date: return datetime.datetime(value.year, value.month, value.day) return value return process class MSDialect_adodbapi(MSDialect): supports_sane_rowcount = True supports_sane_multi_rowcount = True supports_unicode = sys.maxunicode == 65535 supports_unicode_statements = True driver = "adodbapi" @classmethod def import_dbapi(cls): import adodbapi as module return module colspecs = util.update_copy( MSDialect.colspecs, {sqltypes.DateTime: MSDateTime_adodbapi} ) def create_connect_args(self, url): def check_quote(token): if ";" in str(token): token = "'%s'" % token return token keys = dict((k, check_quote(v)) for k, v in url.query.items()) connectors = ["Provider=SQLOLEDB"] if "port" in keys: connectors.append( "Data Source=%s, %s" % (keys.get("host"), keys.get("port")) ) else: connectors.append("Data Source=%s" % keys.get("host")) connectors.append("Initial Catalog=%s" % keys.get("database")) user = keys.get("user") if user: connectors.append("User Id=%s" % user) connectors.append("Password=%s" % keys.get("password", "")) else: connectors.append("Integrated Security=SSPI") return [[";".join(connectors)], {}] def is_disconnect(self, e, connection, cursor): return isinstance( e, self.dbapi.adodbapi.DatabaseError ) and "'connection failure'" in str(e) dialect = MSDialect_adodbapi	2.66 KB	2026-01-20 12:58
📄 base.py # mssql/base.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """ .. dialect:: mssql :name: Microsoft SQL Server .. _mssql_external_dialects: External Dialects ----------------- In addition to the above DBAPI layers with native SQLAlchemy support, there are third-party dialects for other DBAPI layers that are compatible with SQL Server. See the "External Dialects" list on the :ref:`dialect_toplevel` page. .. _mssql_identity: Auto Increment Behavior / IDENTITY Columns ------------------------------------------ SQL Server provides so-called "auto incrementing" behavior using the ``IDENTITY`` construct, which can be placed on any single integer column in a table. SQLAlchemy considers ``IDENTITY`` within its default "autoincrement" behavior for an integer primary key column, described at :paramref:`_schema.Column.autoincrement`. This means that by default, the first integer primary key column in a :class:`_schema.Table` will be considered to be the identity column and will generate DDL as such:: from sqlalchemy import Table, MetaData, Column, Integer m = MetaData() t = Table('t', m, Column('id', Integer, primary_key=True), Column('x', Integer)) m.create_all(engine) The above example will generate DDL as: .. sourcecode:: sql CREATE TABLE t ( id INTEGER NOT NULL IDENTITY(1,1), x INTEGER NULL, PRIMARY KEY (id) ) For the case where this default generation of ``IDENTITY`` is not desired, specify ``False`` for the :paramref:`_schema.Column.autoincrement` flag, on the first integer primary key column:: m = MetaData() t = Table('t', m, Column('id', Integer, primary_key=True, autoincrement=False), Column('x', Integer)) m.create_all(engine) To add the ``IDENTITY`` keyword to a non-primary key column, specify ``True`` for the :paramref:`_schema.Column.autoincrement` flag on the desired :class:`_schema.Column` object, and ensure that :paramref:`_schema.Column.autoincrement` is set to ``False`` on any integer primary key column:: m = MetaData() t = Table('t', m, Column('id', Integer, primary_key=True, autoincrement=False), Column('x', Integer, autoincrement=True)) m.create_all(engine) .. versionchanged:: 1.3 Added ``mssql_identity_start`` and ``mssql_identity_increment`` parameters to :class:`_schema.Column`. These replace the use of the :class:`.Sequence` object in order to specify these values. .. deprecated:: 1.3 The use of :class:`.Sequence` to specify IDENTITY characteristics is deprecated and will be removed in a future release. Please use the ``mssql_identity_start`` and ``mssql_identity_increment`` parameters documented at :ref:`mssql_identity`. .. note:: There can only be one IDENTITY column on the table. When using ``autoincrement=True`` to enable the IDENTITY keyword, SQLAlchemy does not guard against multiple columns specifying the option simultaneously. The SQL Server database will instead reject the ``CREATE TABLE`` statement. .. note:: An INSERT statement which attempts to provide a value for a column that is marked with IDENTITY will be rejected by SQL Server. In order for the value to be accepted, a session-level option "SET IDENTITY_INSERT" must be enabled. The SQLAlchemy SQL Server dialect will perform this operation automatically when using a core :class:`_expression.Insert` construct; if the execution specifies a value for the IDENTITY column, the "IDENTITY_INSERT" option will be enabled for the span of that statement's invocation.However, this scenario is not high performing and should not be relied upon for normal use. If a table doesn't actually require IDENTITY behavior in its integer primary key column, the keyword should be disabled when creating the table by ensuring that ``autoincrement=False`` is set. Controlling "Start" and "Increment" ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Specific control over the "start" and "increment" values for the ``IDENTITY`` generator are provided using the ``mssql_identity_start`` and ``mssql_identity_increment`` parameters passed to the :class:`_schema.Column` object:: from sqlalchemy import Table, Integer, Column test = Table( 'test', metadata, Column( 'id', Integer, primary_key=True, mssql_identity_start=100, mssql_identity_increment=10 ), Column('name', String(20)) ) The CREATE TABLE for the above :class:`_schema.Table` object would be: .. sourcecode:: sql CREATE TABLE test ( id INTEGER NOT NULL IDENTITY(100,10) PRIMARY KEY, name VARCHAR(20) NULL, ) .. versionchanged:: 1.3 The ``mssql_identity_start`` and ``mssql_identity_increment`` parameters are now used to affect the ``IDENTITY`` generator for a :class:`_schema.Column` under SQL Server. Previously, the :class:`.Sequence` object was used. As SQL Server now supports real sequences as a separate construct, :class:`.Sequence` will be functional in the normal way in a future SQLAlchemy version. INSERT behavior ^^^^^^^^^^^^^^^^ Handling of the ``IDENTITY`` column at INSERT time involves two key techniques. The most common is being able to fetch the "last inserted value" for a given ``IDENTITY`` column, a process which SQLAlchemy performs implicitly in many cases, most importantly within the ORM. The process for fetching this value has several variants: * In the vast majority of cases, RETURNING is used in conjunction with INSERT statements on SQL Server in order to get newly generated primary key values: .. sourcecode:: sql INSERT INTO t (x) OUTPUT inserted.id VALUES (?) * When RETURNING is not available or has been disabled via ``implicit_returning=False``, either the ``scope_identity()`` function or the ``@@identity`` variable is used; behavior varies by backend: * when using PyODBC, the phrase ``; select scope_identity()`` will be appended to the end of the INSERT statement; a second result set will be fetched in order to receive the value. Given a table as:: t = Table('t', m, Column('id', Integer, primary_key=True), Column('x', Integer), implicit_returning=False) an INSERT will look like: .. sourcecode:: sql INSERT INTO t (x) VALUES (?); select scope_identity() * Other dialects such as pymssql will call upon ``SELECT scope_identity() AS lastrowid`` subsequent to an INSERT statement. If the flag ``use_scope_identity=False`` is passed to :func:`_sa.create_engine`, the statement ``SELECT @@identity AS lastrowid`` is used instead. A table that contains an ``IDENTITY`` column will prohibit an INSERT statement that refers to the identity column explicitly. The SQLAlchemy dialect will detect when an INSERT construct, created using a core :func:`_expression.insert` construct (not a plain string SQL), refers to the identity column, and in this case will emit ``SET IDENTITY_INSERT ON`` prior to the insert statement proceeding, and ``SET IDENTITY_INSERT OFF`` subsequent to the execution. Given this example:: m = MetaData() t = Table('t', m, Column('id', Integer, primary_key=True), Column('x', Integer)) m.create_all(engine) with engine.begin() as conn: conn.execute(t.insert(), {'id': 1, 'x':1}, {'id':2, 'x':2}) The above column will be created with IDENTITY, however the INSERT statement we emit is specifying explicit values. In the echo output we can see how SQLAlchemy handles this: .. sourcecode:: sql CREATE TABLE t ( id INTEGER NOT NULL IDENTITY(1,1), x INTEGER NULL, PRIMARY KEY (id) ) COMMIT SET IDENTITY_INSERT t ON INSERT INTO t (id, x) VALUES (?, ?) ((1, 1), (2, 2)) SET IDENTITY_INSERT t OFF COMMIT This is an auxiliary use case suitable for testing and bulk insert scenarios. MAX on VARCHAR / NVARCHAR ------------------------- SQL Server supports the special string "MAX" within the :class:`_types.VARCHAR` and :class:`_types.NVARCHAR` datatypes, to indicate "maximum length possible". The dialect currently handles this as a length of "None" in the base type, rather than supplying a dialect-specific version of these types, so that a base type specified such as ``VARCHAR(None)`` can assume "unlengthed" behavior on more than one backend without using dialect-specific types. To build a SQL Server VARCHAR or NVARCHAR with MAX length, use None:: my_table = Table( 'my_table', metadata, Column('my_data', VARCHAR(None)), Column('my_n_data', NVARCHAR(None)) ) Collation Support ----------------- Character collations are supported by the base string types, specified by the string argument "collation":: from sqlalchemy import VARCHAR Column('login', VARCHAR(32, collation='Latin1_General_CI_AS')) When such a column is associated with a :class:`_schema.Table`, the CREATE TABLE statement for this column will yield:: login VARCHAR(32) COLLATE Latin1_General_CI_AS NULL LIMIT/OFFSET Support -------------------- MSSQL has no support for the LIMIT or OFFSET keywords. LIMIT is supported directly through the ``TOP`` Transact SQL keyword:: select.limit will yield:: SELECT TOP n If using SQL Server 2005 or above, LIMIT with OFFSET support is available through the ``ROW_NUMBER OVER`` construct. For versions below 2005, LIMIT with OFFSET usage will fail. .. _mssql_isolation_level: Transaction Isolation Level --------------------------- All SQL Server dialects support setting of transaction isolation level both via a dialect-specific parameter :paramref:`_sa.create_engine.isolation_level` accepted by :func:`_sa.create_engine`, as well as the :paramref:`.Connection.execution_options.isolation_level` argument as passed to :meth:`_engine.Connection.execution_options`. This feature works by issuing the command ``SET TRANSACTION ISOLATION LEVEL <level>`` for each new connection. To set isolation level using :func:`_sa.create_engine`:: engine = create_engine( "mssql+pyodbc://scott:tiger@ms_2008", isolation_level="REPEATABLE READ" ) To set using per-connection execution options:: connection = engine.connect() connection = connection.execution_options( isolation_level="READ COMMITTED" ) Valid values for ``isolation_level`` include: * ``AUTOCOMMIT`` - pyodbc / pymssql-specific * ``READ COMMITTED`` * ``READ UNCOMMITTED`` * ``REPEATABLE READ`` * ``SERIALIZABLE`` * ``SNAPSHOT`` - specific to SQL Server .. versionadded:: 1.2 added AUTOCOMMIT isolation level setting .. seealso:: :ref:`dbapi_autocommit` Nullability ----------- MSSQL has support for three levels of column nullability. The default nullability allows nulls and is explicit in the CREATE TABLE construct:: name VARCHAR(20) NULL If ``nullable=None`` is specified then no specification is made. In other words the database's configured default is used. This will render:: name VARCHAR(20) If ``nullable`` is ``True`` or ``False`` then the column will be ``NULL`` or ``NOT NULL`` respectively. Date / Time Handling -------------------- DATE and TIME are supported. Bind parameters are converted to datetime.datetime() objects as required by most MSSQL drivers, and results are processed from strings if needed. The DATE and TIME types are not available for MSSQL 2005 and previous - if a server version below 2008 is detected, DDL for these types will be issued as DATETIME. .. _mssql_large_type_deprecation: Large Text/Binary Type Deprecation ---------------------------------- Per `SQL Server 2012/2014 Documentation <http://technet.microsoft.com/en-us/library/ms187993.aspx>`_, the ``NTEXT``, ``TEXT`` and ``IMAGE`` datatypes are to be removed from SQL Server in a future release. SQLAlchemy normally relates these types to the :class:`.UnicodeText`, :class:`_expression.TextClause` and :class:`.LargeBinary` datatypes. In order to accommodate this change, a new flag ``deprecate_large_types`` is added to the dialect, which will be automatically set based on detection of the server version in use, if not otherwise set by the user. The behavior of this flag is as follows: * When this flag is ``True``, the :class:`.UnicodeText`, :class:`_expression.TextClause` and :class:`.LargeBinary` datatypes, when used to render DDL, will render the types ``NVARCHAR(max)``, ``VARCHAR(max)``, and ``VARBINARY(max)``, respectively. This is a new behavior as of the addition of this flag. * When this flag is ``False``, the :class:`.UnicodeText`, :class:`_expression.TextClause` and :class:`.LargeBinary` datatypes, when used to render DDL, will render the types ``NTEXT``, ``TEXT``, and ``IMAGE``, respectively. This is the long-standing behavior of these types. * The flag begins with the value ``None``, before a database connection is established. If the dialect is used to render DDL without the flag being set, it is interpreted the same as ``False``. * On first connection, the dialect detects if SQL Server version 2012 or greater is in use; if the flag is still at ``None``, it sets it to ``True`` or ``False`` based on whether 2012 or greater is detected. * The flag can be set to either ``True`` or ``False`` when the dialect is created, typically via :func:`_sa.create_engine`:: eng = create_engine("mssql+pymssql://user:pass@host/db", deprecate_large_types=True) * Complete control over whether the "old" or "new" types are rendered is available in all SQLAlchemy versions by using the UPPERCASE type objects instead: :class:`_types.NVARCHAR`, :class:`_types.VARCHAR`, :class:`_types.VARBINARY`, :class:`_types.TEXT`, :class:`_mssql.NTEXT`, :class:`_mssql.IMAGE` will always remain fixed and always output exactly that type. .. versionadded:: 1.0.0 .. _multipart_schema_names: Multipart Schema Names ---------------------- SQL Server schemas sometimes require multiple parts to their "schema" qualifier, that is, including the database name and owner name as separate tokens, such as ``mydatabase.dbo.some_table``. These multipart names can be set at once using the :paramref:`_schema.Table.schema` argument of :class:`_schema.Table`:: Table( "some_table", metadata, Column("q", String(50)), schema="mydatabase.dbo" ) When performing operations such as table or component reflection, a schema argument that contains a dot will be split into separate "database" and "owner" components in order to correctly query the SQL Server information schema tables, as these two values are stored separately. Additionally, when rendering the schema name for DDL or SQL, the two components will be quoted separately for case sensitive names and other special characters. Given an argument as below:: Table( "some_table", metadata, Column("q", String(50)), schema="MyDataBase.dbo" ) The above schema would be rendered as ``[MyDataBase].dbo``, and also in reflection, would be reflected using "dbo" as the owner and "MyDataBase" as the database name. To control how the schema name is broken into database / owner, specify brackets (which in SQL Server are quoting characters) in the name. Below, the "owner" will be considered as ``MyDataBase.dbo`` and the "database" will be None:: Table( "some_table", metadata, Column("q", String(50)), schema="[MyDataBase.dbo]" ) To individually specify both database and owner name with special characters or embedded dots, use two sets of brackets:: Table( "some_table", metadata, Column("q", String(50)), schema="[MyDataBase.Period].[MyOwner.Dot]" ) .. versionchanged:: 1.2 the SQL Server dialect now treats brackets as identifier delimeters splitting the schema into separate database and owner tokens, to allow dots within either name itself. .. _legacy_schema_rendering: Legacy Schema Mode ------------------ Very old versions of the MSSQL dialect introduced the behavior such that a schema-qualified table would be auto-aliased when used in a SELECT statement; given a table:: account_table = Table( 'account', metadata, Column('id', Integer, primary_key=True), Column('info', String(100)), schema="customer_schema" ) this legacy mode of rendering would assume that "customer_schema.account" would not be accepted by all parts of the SQL statement, as illustrated below:: >>> eng = create_engine("mssql+pymssql://mydsn", legacy_schema_aliasing=True) >>> print(account_table.select().compile(eng)) SELECT account_1.id, account_1.info FROM customer_schema.account AS account_1 This mode of behavior is now off by default, as it appears to have served no purpose; however in the case that legacy applications rely upon it, it is available using the ``legacy_schema_aliasing`` argument to :func:`_sa.create_engine` as illustrated above. .. versionchanged:: 1.1 the ``legacy_schema_aliasing`` flag introduced in version 1.0.5 to allow disabling of legacy mode for schemas now defaults to False. .. _mssql_indexes: Clustered Index Support ----------------------- The MSSQL dialect supports clustered indexes (and primary keys) via the ``mssql_clustered`` option. This option is available to :class:`.Index`, :class:`.UniqueConstraint`. and :class:`.PrimaryKeyConstraint`. To generate a clustered index:: Index("my_index", table.c.x, mssql_clustered=True) which renders the index as ``CREATE CLUSTERED INDEX my_index ON table (x)``. To generate a clustered primary key use:: Table('my_table', metadata, Column('x', ...), Column('y', ...), PrimaryKeyConstraint("x", "y", mssql_clustered=True)) which will render the table, for example, as:: CREATE TABLE my_table (x INTEGER NOT NULL, y INTEGER NOT NULL, PRIMARY KEY CLUSTERED (x, y)) Similarly, we can generate a clustered unique constraint using:: Table('my_table', metadata, Column('x', ...), Column('y', ...), PrimaryKeyConstraint("x"), UniqueConstraint("y", mssql_clustered=True), ) To explicitly request a non-clustered primary key (for example, when a separate clustered index is desired), use:: Table('my_table', metadata, Column('x', ...), Column('y', ...), PrimaryKeyConstraint("x", "y", mssql_clustered=False)) which will render the table, for example, as:: CREATE TABLE my_table (x INTEGER NOT NULL, y INTEGER NOT NULL, PRIMARY KEY NONCLUSTERED (x, y)) .. versionchanged:: 1.1 the ``mssql_clustered`` option now defaults to None, rather than False. ``mssql_clustered=False`` now explicitly renders the NONCLUSTERED clause, whereas None omits the CLUSTERED clause entirely, allowing SQL Server defaults to take effect. MSSQL-Specific Index Options ----------------------------- In addition to clustering, the MSSQL dialect supports other special options for :class:`.Index`. INCLUDE ^^^^^^^ The ``mssql_include`` option renders INCLUDE(colname) for the given string names:: Index("my_index", table.c.x, mssql_include=['y']) would render the index as ``CREATE INDEX my_index ON table (x) INCLUDE (y)`` .. _mssql_index_where: Filtered Indexes ^^^^^^^^^^^^^^^^ The ``mssql_where`` option renders WHERE(condition) for the given string names:: Index("my_index", table.c.x, mssql_where=table.c.x > 10) would render the index as ``CREATE INDEX my_index ON table (x) WHERE x > 10``. .. versionadded:: 1.3.4 Index ordering ^^^^^^^^^^^^^^ Index ordering is available via functional expressions, such as:: Index("my_index", table.c.x.desc()) would render the index as ``CREATE INDEX my_index ON table (x DESC)`` .. seealso:: :ref:`schema_indexes_functional` Compatibility Levels -------------------- MSSQL supports the notion of setting compatibility levels at the database level. This allows, for instance, to run a database that is compatible with SQL2000 while running on a SQL2005 database server. ``server_version_info`` will always return the database server version information (in this case SQL2005) and not the compatibility level information. Because of this, if running under a backwards compatibility mode SQLAlchemy may attempt to use T-SQL statements that are unable to be parsed by the database server. Triggers -------- SQLAlchemy by default uses OUTPUT INSERTED to get at newly generated primary key values via IDENTITY columns or other server side defaults. MS-SQL does not allow the usage of OUTPUT INSERTED on tables that have triggers. To disable the usage of OUTPUT INSERTED on a per-table basis, specify ``implicit_returning=False`` for each :class:`_schema.Table` which has triggers:: Table('mytable', metadata, Column('id', Integer, primary_key=True), # ..., implicit_returning=False ) Declarative form:: class MyClass(Base): # ... __table_args__ = {'implicit_returning':False} This option can also be specified engine-wide using the ``implicit_returning=False`` argument on :func:`_sa.create_engine`. .. _mssql_rowcount_versioning: Rowcount Support / ORM Versioning --------------------------------- The SQL Server drivers may have limited ability to return the number of rows updated from an UPDATE or DELETE statement. As of this writing, the PyODBC driver is not able to return a rowcount when OUTPUT INSERTED is used. This impacts the SQLAlchemy ORM's versioning feature in many cases where server-side value generators are in use in that while the versioning operations can succeed, the ORM cannot always check that an UPDATE or DELETE statement matched the number of rows expected, which is how it verifies that the version identifier matched. When this condition occurs, a warning will be emitted but the operation will proceed. The use of OUTPUT INSERTED can be disabled by setting the :paramref:`_schema.Table.implicit_returning` flag to ``False`` on a particular :class:`_schema.Table`, which in declarative looks like:: class MyTable(Base): __tablename__ = 'mytable' id = Column(Integer, primary_key=True) stuff = Column(String(10)) timestamp = Column(TIMESTAMP(), default=text('DEFAULT')) __mapper_args__ = { 'version_id_col': timestamp, 'version_id_generator': False, } __table_args__ = { 'implicit_returning': False } Enabling Snapshot Isolation --------------------------- SQL Server has a default transaction isolation mode that locks entire tables, and causes even mildly concurrent applications to have long held locks and frequent deadlocks. Enabling snapshot isolation for the database as a whole is recommended for modern levels of concurrency support. This is accomplished via the following ALTER DATABASE commands executed at the SQL prompt:: ALTER DATABASE MyDatabase SET ALLOW_SNAPSHOT_ISOLATION ON ALTER DATABASE MyDatabase SET READ_COMMITTED_SNAPSHOT ON Background on SQL Server snapshot isolation is available at http://msdn.microsoft.com/en-us/library/ms175095.aspx. """ # noqa import codecs import datetime import operator import re from . import information_schema as ischema from ... import engine from ... import exc from ... import schema as sa_schema from ... import sql from ... import types as sqltypes from ... import util from ...engine import default from ...engine import reflection from ...sql import compiler from ...sql import expression from ...sql import func from ...sql import quoted_name from ...sql import util as sql_util from ...types import BIGINT from ...types import BINARY from ...types import CHAR from ...types import DATE from ...types import DATETIME from ...types import DECIMAL from ...types import FLOAT from ...types import INTEGER from ...types import NCHAR from ...types import NUMERIC from ...types import NVARCHAR from ...types import SMALLINT from ...types import TEXT from ...types import VARCHAR from ...util import update_wrapper from ...util.langhelpers import public_factory # http://sqlserverbuilds.blogspot.com/ MS_2016_VERSION = (13,) MS_2014_VERSION = (12,) MS_2012_VERSION = (11,) MS_2008_VERSION = (10,) MS_2005_VERSION = (9,) MS_2000_VERSION = (8,) RESERVED_WORDS = set( [ "add", "all", "alter", "and", "any", "as", "asc", "authorization", "backup", "begin", "between", "break", "browse", "bulk", "by", "cascade", "case", "check", "checkpoint", "close", "clustered", "coalesce", "collate", "column", "commit", "compute", "constraint", "contains", "containstable", "continue", "convert", "create", "cross", "current", "current_date", "current_time", "current_timestamp", "current_user", "cursor", "database", "dbcc", "deallocate", "declare", "default", "delete", "deny", "desc", "disk", "distinct", "distributed", "double", "drop", "dump", "else", "end", "errlvl", "escape", "except", "exec", "execute", "exists", "exit", "external", "fetch", "file", "fillfactor", "for", "foreign", "freetext", "freetexttable", "from", "full", "function", "goto", "grant", "group", "having", "holdlock", "identity", "identity_insert", "identitycol", "if", "in", "index", "inner", "insert", "intersect", "into", "is", "join", "key", "kill", "left", "like", "lineno", "load", "merge", "national", "nocheck", "nonclustered", "not", "null", "nullif", "of", "off", "offsets", "on", "open", "opendatasource", "openquery", "openrowset", "openxml", "option", "or", "order", "outer", "over", "percent", "pivot", "plan", "precision", "primary", "print", "proc", "procedure", "public", "raiserror", "read", "readtext", "reconfigure", "references", "replication", "restore", "restrict", "return", "revert", "revoke", "right", "rollback", "rowcount", "rowguidcol", "rule", "save", "schema", "securityaudit", "select", "session_user", "set", "setuser", "shutdown", "some", "statistics", "system_user", "table", "tablesample", "textsize", "then", "to", "top", "tran", "transaction", "trigger", "truncate", "tsequal", "union", "unique", "unpivot", "update", "updatetext", "use", "user", "values", "varying", "view", "waitfor", "when", "where", "while", "with", "writetext", ] ) class REAL(sqltypes.REAL): __visit_name__ = "REAL" def __init__(self, kw): # REAL is a synonym for FLOAT(24) on SQL server. # it is only accepted as the word "REAL" in DDL, the numeric # precision value is not allowed to be present kw.setdefault("precision", 24) super(REAL, self).__init__(kw) class TINYINT(sqltypes.Integer): __visit_name__ = "TINYINT" # MSSQL DATE/TIME types have varied behavior, sometimes returning # strings. MSDate/TIME check for everything, and always # filter bind parameters into datetime objects (required by pyodbc, # not sure about other dialects). class _MSDate(sqltypes.Date): def bind_processor(self, dialect): def process(value): if type(value) == datetime.date: return datetime.datetime(value.year, value.month, value.day) else: return value return process _reg = re.compile(r"(\d+)-(\d+)-(\d+)") def result_processor(self, dialect, coltype): def process(value): if isinstance(value, datetime.datetime): return value.date() elif isinstance(value, util.string_types): m = self._reg.match(value) if not m: raise ValueError( "could not parse %r as a date value" % (value,) ) return datetime.date([int(x or 0) for x in m.groups()]) else: return value return process class TIME(sqltypes.TIME): def __init__(self, precision=None, kwargs): self.precision = precision super(TIME, self).__init__() __zero_date = datetime.date(1900, 1, 1) def bind_processor(self, dialect): def process(value): if isinstance(value, datetime.datetime): value = datetime.datetime.combine( self.__zero_date, value.time() ) elif isinstance(value, datetime.time): """issue #5339 per: https://github.com/mkleehammer/pyodbc/wiki/Tips-and-Tricks-by-Database-Platform#time-columns pass TIME value as string """ # noqa value = str(value) return value return process _reg = re.compile(r"(\d+):(\d+):(\d+)(?:\.(\d{0,6}))?") def result_processor(self, dialect, coltype): def process(value): if isinstance(value, datetime.datetime): return value.time() elif isinstance(value, util.string_types): m = self._reg.match(value) if not m: raise ValueError( "could not parse %r as a time value" % (value,) ) return datetime.time([int(x or 0) for x in m.groups()]) else: return value return process _MSTime = TIME class _DateTimeBase(object): def bind_processor(self, dialect): def process(value): if type(value) == datetime.date: return datetime.datetime(value.year, value.month, value.day) else: return value return process class _MSDateTime(_DateTimeBase, sqltypes.DateTime): pass class SMALLDATETIME(_DateTimeBase, sqltypes.DateTime): __visit_name__ = "SMALLDATETIME" class DATETIME2(_DateTimeBase, sqltypes.DateTime): __visit_name__ = "DATETIME2" def __init__(self, precision=None, kw): super(DATETIME2, self).__init__(kw) self.precision = precision # TODO: is this not an Interval ? class DATETIMEOFFSET(sqltypes.TypeEngine): __visit_name__ = "DATETIMEOFFSET" def __init__(self, precision=None, kwargs): self.precision = precision class _UnicodeLiteral(object): def literal_processor(self, dialect): def process(value): value = value.replace("'", "''") if dialect.identifier_preparer._double_percents: value = value.replace("%", "%%") return "N'%s'" % value return process class _MSUnicode(_UnicodeLiteral, sqltypes.Unicode): pass class _MSUnicodeText(_UnicodeLiteral, sqltypes.UnicodeText): pass class TIMESTAMP(sqltypes._Binary): """Implement the SQL Server TIMESTAMP type. Note this is completely different than the SQL Standard TIMESTAMP type, which is not supported by SQL Server. It is a read-only datatype that does not support INSERT of values. .. versionadded:: 1.2 .. seealso:: :class:`_mssql.ROWVERSION` """ __visit_name__ = "TIMESTAMP" # expected by _Binary to be present length = None def __init__(self, convert_int=False): """Construct a TIMESTAMP or ROWVERSION type. :param convert_int: if True, binary integer values will be converted to integers on read. .. versionadded:: 1.2 """ self.convert_int = convert_int def result_processor(self, dialect, coltype): super_ = super(TIMESTAMP, self).result_processor(dialect, coltype) if self.convert_int: def process(value): value = super_(value) if value is not None: # https://stackoverflow.com/a/30403242/34549 value = int(codecs.encode(value, "hex"), 16) return value return process else: return super_ class ROWVERSION(TIMESTAMP): """Implement the SQL Server ROWVERSION type. The ROWVERSION datatype is a SQL Server synonym for the TIMESTAMP datatype, however current SQL Server documentation suggests using ROWVERSION for new datatypes going forward. The ROWVERSION datatype does not** reflect (e.g. introspect) from the database as itself; the returned datatype will be :class:`_mssql.TIMESTAMP`. This is a read-only datatype that does not support INSERT of values. .. versionadded:: 1.2 .. seealso:: :class:`_mssql.TIMESTAMP` """ __visit_name__ = "ROWVERSION" class NTEXT(sqltypes.UnicodeText): """MSSQL NTEXT type, for variable-length unicode text up to 2^30 characters.""" __visit_name__ = "NTEXT" class VARBINARY(sqltypes.VARBINARY, sqltypes.LargeBinary): """The MSSQL VARBINARY type. This type is present to support "deprecate_large_types" mode where either ``VARBINARY(max)`` or IMAGE is rendered. Otherwise, this type object is redundant vs. :class:`_types.VARBINARY`. .. versionadded:: 1.0.0 .. seealso:: :ref:`mssql_large_type_deprecation` """ __visit_name__ = "VARBINARY" class IMAGE(sqltypes.LargeBinary): __visit_name__ = "IMAGE" class XML(sqltypes.Text): """MSSQL XML type. This is a placeholder type for reflection purposes that does not include any Python-side datatype support. It also does not currently support additional arguments, such as "CONTENT", "DOCUMENT", "xml_schema_collection". .. versionadded:: 1.1.11 """ __visit_name__ = "XML" class BIT(sqltypes.TypeEngine): __visit_name__ = "BIT" class MONEY(sqltypes.TypeEngine): __visit_name__ = "MONEY" class SMALLMONEY(sqltypes.TypeEngine): __visit_name__ = "SMALLMONEY" class UNIQUEIDENTIFIER(sqltypes.TypeEngine): __visit_name__ = "UNIQUEIDENTIFIER" class SQL_VARIANT(sqltypes.TypeEngine): __visit_name__ = "SQL_VARIANT" class TryCast(sql.elements.Cast): """Represent a SQL Server TRY_CAST expression.""" __visit_name__ = "try_cast" def __init__(self, arg, kw): """Create a TRY_CAST expression. :class:`.TryCast` is a subclass of SQLAlchemy's :class:`.Cast` construct, and works in the same way, except that the SQL expression rendered is "TRY_CAST" rather than "CAST":: from sqlalchemy import select from sqlalchemy import Numeric from sqlalchemy.dialects.mssql import try_cast stmt = select([ try_cast(product_table.c.unit_price, Numeric(10, 4)) ]) The above would render:: SELECT TRY_CAST (product_table.unit_price AS NUMERIC(10, 4)) FROM product_table .. versionadded:: 1.3.7 """ super(TryCast, self).__init__(arg, kw) try_cast = public_factory(TryCast, ".dialects.mssql.try_cast") # old names. MSDateTime = _MSDateTime MSDate = _MSDate MSReal = REAL MSTinyInteger = TINYINT MSTime = TIME MSSmallDateTime = SMALLDATETIME MSDateTime2 = DATETIME2 MSDateTimeOffset = DATETIMEOFFSET MSText = TEXT MSNText = NTEXT MSString = VARCHAR MSNVarchar = NVARCHAR MSChar = CHAR MSNChar = NCHAR MSBinary = BINARY MSVarBinary = VARBINARY MSImage = IMAGE MSBit = BIT MSMoney = MONEY MSSmallMoney = SMALLMONEY MSUniqueIdentifier = UNIQUEIDENTIFIER MSVariant = SQL_VARIANT ischema_names = { "int": INTEGER, "bigint": BIGINT, "smallint": SMALLINT, "tinyint": TINYINT, "varchar": VARCHAR, "nvarchar": NVARCHAR, "char": CHAR, "nchar": NCHAR, "text": TEXT, "ntext": NTEXT, "decimal": DECIMAL, "numeric": NUMERIC, "float": FLOAT, "datetime": DATETIME, "datetime2": DATETIME2, "datetimeoffset": DATETIMEOFFSET, "date": DATE, "time": TIME, "smalldatetime": SMALLDATETIME, "binary": BINARY, "varbinary": VARBINARY, "bit": BIT, "real": REAL, "image": IMAGE, "xml": XML, "timestamp": TIMESTAMP, "money": MONEY, "smallmoney": SMALLMONEY, "uniqueidentifier": UNIQUEIDENTIFIER, "sql_variant": SQL_VARIANT, } class MSTypeCompiler(compiler.GenericTypeCompiler): def _extend(self, spec, type_, length=None): """Extend a string-type declaration with standard SQL COLLATE annotations. """ if getattr(type_, "collation", None): collation = "COLLATE %s" % type_.collation else: collation = None if not length: length = type_.length if length: spec = spec + "(%s)" % length return " ".join([c for c in (spec, collation) if c is not None]) def visit_FLOAT(self, type_, kw): precision = getattr(type_, "precision", None) if precision is None: return "FLOAT" else: return "FLOAT(%(precision)s)" % {"precision": precision} def visit_TINYINT(self, type_, kw): return "TINYINT" def visit_DATETIMEOFFSET(self, type_, kw): if type_.precision is not None: return "DATETIMEOFFSET(%s)" % type_.precision else: return "DATETIMEOFFSET" def visit_TIME(self, type_, kw): precision = getattr(type_, "precision", None) if precision is not None: return "TIME(%s)" % precision else: return "TIME" def visit_TIMESTAMP(self, type_, kw): return "TIMESTAMP" def visit_ROWVERSION(self, type_, kw): return "ROWVERSION" def visit_DATETIME2(self, type_, kw): precision = getattr(type_, "precision", None) if precision is not None: return "DATETIME2(%s)" % precision else: return "DATETIME2" def visit_SMALLDATETIME(self, type_, kw): return "SMALLDATETIME" def visit_unicode(self, type_, kw): return self.visit_NVARCHAR(type_, kw) def visit_text(self, type_, kw): if self.dialect.deprecate_large_types: return self.visit_VARCHAR(type_, kw) else: return self.visit_TEXT(type_, kw) def visit_unicode_text(self, type_, kw): if self.dialect.deprecate_large_types: return self.visit_NVARCHAR(type_, kw) else: return self.visit_NTEXT(type_, kw) def visit_NTEXT(self, type_, kw): return self._extend("NTEXT", type_) def visit_TEXT(self, type_, kw): return self._extend("TEXT", type_) def visit_VARCHAR(self, type_, kw): return self._extend("VARCHAR", type_, length=type_.length or "max") def visit_CHAR(self, type_, kw): return self._extend("CHAR", type_) def visit_NCHAR(self, type_, kw): return self._extend("NCHAR", type_) def visit_NVARCHAR(self, type_, kw): return self._extend("NVARCHAR", type_, length=type_.length or "max") def visit_date(self, type_, kw): if self.dialect.server_version_info < MS_2008_VERSION: return self.visit_DATETIME(type_, kw) else: return self.visit_DATE(type_, kw) def visit_time(self, type_, kw): if self.dialect.server_version_info < MS_2008_VERSION: return self.visit_DATETIME(type_, kw) else: return self.visit_TIME(type_, kw) def visit_large_binary(self, type_, kw): if self.dialect.deprecate_large_types: return self.visit_VARBINARY(type_, kw) else: return self.visit_IMAGE(type_, kw) def visit_IMAGE(self, type_, kw): return "IMAGE" def visit_XML(self, type_, kw): return "XML" def visit_VARBINARY(self, type_, kw): return self._extend("VARBINARY", type_, length=type_.length or "max") def visit_boolean(self, type_, kw): return self.visit_BIT(type_) def visit_BIT(self, type_, kw): return "BIT" def visit_MONEY(self, type_, kw): return "MONEY" def visit_SMALLMONEY(self, type_, kw): return "SMALLMONEY" def visit_UNIQUEIDENTIFIER(self, type_, kw): return "UNIQUEIDENTIFIER" def visit_SQL_VARIANT(self, type_, *kw): return "SQL_VARIANT" class MSExecutionContext(default.DefaultExecutionContext): _enable_identity_insert = False _select_lastrowid = False _result_proxy = None _lastrowid = None def _opt_encode(self, statement): if not self.dialect.supports_unicode_statements: return self.dialect._encoder(statement)[0] else: return statement def pre_exec(self): """Activate IDENTITY_INSERT if needed.""" if self.isinsert: tbl = self.compiled.statement.table seq_column = tbl._autoincrement_column insert_has_sequence = seq_column is not None if insert_has_sequence: self._enable_identity_insert = ( seq_column.key in self.compiled_parameters[0] ) or ( self.compiled.statement.parameters and ( ( self.compiled.statement._has_multi_parameters and ( seq_column.key in self.compiled.statement.parameters[0] or seq_column in self.compiled.statement.parameters[0] ) ) or ( not self.compiled.statement._has_multi_parameters and ( seq_column.key in self.compiled.statement.parameters or seq_column in self.compiled.statement.parameters ) ) ) ) else: self._enable_identity_insert = False self._select_lastrowid = ( not self.compiled.inline and insert_has_sequence and not self.compiled.returning and not self._enable_identity_insert and not self.executemany ) if self._enable_identity_insert: self.root_connection._cursor_execute( self.cursor, self._opt_encode( "SET IDENTITY_INSERT %s ON" % self.identifier_preparer.format_table(tbl) ), (), self, ) def post_exec(self): """Disable IDENTITY_INSERT if enabled.""" conn = self.root_connection if self._select_lastrowid: if self.dialect.use_scope_identity: conn._cursor_execute( self.cursor, "SELECT scope_identity() AS lastrowid", (), self, ) else: conn._cursor_execute( self.cursor, "SELECT @@identity AS lastrowid", (), self ) # fetchall() ensures the cursor is consumed without closing it row = self.cursor.fetchall()[0] self._lastrowid = int(row[0]) if ( self.isinsert or self.isupdate or self.isdelete ) and self.compiled.returning: self._result_proxy = engine.FullyBufferedResultProxy(self) if self._enable_identity_insert: conn._cursor_execute( self.cursor, self._opt_encode( "SET IDENTITY_INSERT %s OFF" % self.identifier_preparer.format_table( self.compiled.statement.table ) ), (), self, ) def get_lastrowid(self): return self._lastrowid def handle_dbapi_exception(self, e): if self._enable_identity_insert: try: self.cursor.execute( self._opt_encode( "SET IDENTITY_INSERT %s OFF" % self.identifier_preparer.format_table( self.compiled.statement.table ) ) ) except Exception: pass def get_result_proxy(self): if self._result_proxy: return self._result_proxy else: return engine.ResultProxy(self) class MSSQLCompiler(compiler.SQLCompiler): returning_precedes_values = True extract_map = util.update_copy( compiler.SQLCompiler.extract_map, { "doy": "dayofyear", "dow": "weekday", "milliseconds": "millisecond", "microseconds": "microsecond", }, ) def __init__(self, args, *kwargs): self.tablealiases = {} super(MSSQLCompiler, self).__init__(args, *kwargs) def _with_legacy_schema_aliasing(fn): def decorate(self, arg, *kw): if self.dialect.legacy_schema_aliasing: return fn(self, arg, *kw) else: super_ = getattr(super(MSSQLCompiler, self), fn.__name__) return super_(arg, kw) return decorate def visit_now_func(self, fn, kw): return "CURRENT_TIMESTAMP" def visit_current_date_func(self, fn, kw): return "GETDATE()" def visit_length_func(self, fn, kw): return "LEN%s" % self.function_argspec(fn, kw) def visit_char_length_func(self, fn, kw): return "LEN%s" % self.function_argspec(fn, kw) def visit_concat_op_binary(self, binary, operator, kw): return "%s + %s" % ( self.process(binary.left, kw), self.process(binary.right, kw), ) def visit_true(self, expr, kw): return "1" def visit_false(self, expr, kw): return "0" def visit_match_op_binary(self, binary, operator, kw): return "CONTAINS (%s, %s)" % ( self.process(binary.left, kw), self.process(binary.right, kw), ) def get_select_precolumns(self, select, kw): """ MS-SQL puts TOP, it's version of LIMIT here """ s = "" if select._distinct: s += "DISTINCT " if select._simple_int_limit and ( select._offset_clause is None or (select._simple_int_offset and select._offset == 0) ): # ODBC drivers and possibly others # don't support bind params in the SELECT clause on SQL Server. # so have to use literal here. s += "TOP %d " % select._limit if s: return s else: return compiler.SQLCompiler.get_select_precolumns( self, select, kw ) def get_from_hint_text(self, table, text): return text def get_crud_hint_text(self, table, text): return text def limit_clause(self, select, kw): # Limit in mssql is after the select keyword return "" def visit_try_cast(self, element, kw): return "TRY_CAST (%s AS %s)" % ( self.process(element.clause, kw), self.process(element.typeclause, kw), ) def visit_select(self, select, kwargs): """Look for ``LIMIT`` and OFFSET in a select statement, and if so tries to wrap it in a subquery with ``row_number()`` criterion. """ if ( (not select._simple_int_limit and select._limit_clause is not None) or ( select._offset_clause is not None and not select._simple_int_offset or select._offset ) ) and not getattr(select, "_mssql_visit", None): # to use ROW_NUMBER(), an ORDER BY is required. if not select._order_by_clause.clauses: raise exc.CompileError( "MSSQL requires an order_by when " "using an OFFSET or a non-simple " "LIMIT clause" ) _order_by_clauses = [ sql_util.unwrap_label_reference(elem) for elem in select._order_by_clause.clauses ] limit_clause = select._limit_clause offset_clause = select._offset_clause kwargs["select_wraps_for"] = select select = select._generate() select._mssql_visit = True select = ( select.column( sql.func.ROW_NUMBER() .over(order_by=_order_by_clauses) .label("mssql_rn") ) .order_by(None) .alias() ) mssql_rn = sql.column("mssql_rn") limitselect = sql.select( [c for c in select.c if c.key != "mssql_rn"] ) if offset_clause is not None: limitselect.append_whereclause(mssql_rn > offset_clause) if limit_clause is not None: limitselect.append_whereclause( mssql_rn <= (limit_clause + offset_clause) ) else: limitselect.append_whereclause(mssql_rn <= (limit_clause)) return self.process(limitselect, kwargs) else: return compiler.SQLCompiler.visit_select(self, select, kwargs) @_with_legacy_schema_aliasing def visit_table(self, table, mssql_aliased=False, iscrud=False, kwargs): if mssql_aliased is table or iscrud: return super(MSSQLCompiler, self).visit_table(table, kwargs) # alias schema-qualified tables alias = self._schema_aliased_table(table) if alias is not None: return self.process(alias, mssql_aliased=table, kwargs) else: return super(MSSQLCompiler, self).visit_table(table, kwargs) @_with_legacy_schema_aliasing def visit_alias(self, alias, kw): # translate for schema-qualified table aliases kw["mssql_aliased"] = alias.original return super(MSSQLCompiler, self).visit_alias(alias, kw) @_with_legacy_schema_aliasing def visit_column(self, column, add_to_result_map=None, kw): if ( column.table is not None and (not self.isupdate and not self.isdelete) or self.is_subquery() ): # translate for schema-qualified table aliases t = self._schema_aliased_table(column.table) if t is not None: converted = expression._corresponding_column_or_error( t, column ) if add_to_result_map is not None: add_to_result_map( column.name, column.name, (column, column.name, column.key), column.type, ) return super(MSSQLCompiler, self).visit_column(converted, kw) return super(MSSQLCompiler, self).visit_column( column, add_to_result_map=add_to_result_map, kw ) def _schema_aliased_table(self, table): if getattr(table, "schema", None) is not None: if table not in self.tablealiases: self.tablealiases[table] = table.alias() return self.tablealiases[table] else: return None def visit_extract(self, extract, kw): field = self.extract_map.get(extract.field, extract.field) return "DATEPART(%s, %s)" % (field, self.process(extract.expr, kw)) def visit_savepoint(self, savepoint_stmt): return "SAVE TRANSACTION %s" % self.preparer.format_savepoint( savepoint_stmt ) def visit_rollback_to_savepoint(self, savepoint_stmt): return "ROLLBACK TRANSACTION %s" % self.preparer.format_savepoint( savepoint_stmt ) def visit_binary(self, binary, kwargs): """Move bind parameters to the right-hand side of an operator, where possible. """ if ( isinstance(binary.left, expression.BindParameter) and binary.operator == operator.eq and not isinstance(binary.right, expression.BindParameter) ): return self.process( expression.BinaryExpression( binary.right, binary.left, binary.operator ), kwargs ) return super(MSSQLCompiler, self).visit_binary(binary, kwargs) def returning_clause(self, stmt, returning_cols): if self.isinsert or self.isupdate: target = stmt.table.alias("inserted") else: target = stmt.table.alias("deleted") adapter = sql_util.ClauseAdapter(target) columns = [ self._label_select_column( None, adapter.traverse(c), True, False, {} ) for c in expression._select_iterables(returning_cols) ] return "OUTPUT " + ", ".join(columns) def get_cte_preamble(self, recursive): # SQL Server finds it too inconvenient to accept # an entirely optional, SQL standard specified, # "RECURSIVE" word with their "WITH", # so here we go return "WITH" def label_select_column(self, select, column, asfrom): if isinstance(column, expression.Function): return column.label(None) else: return super(MSSQLCompiler, self).label_select_column( select, column, asfrom ) def for_update_clause(self, select): # "FOR UPDATE" is only allowed on "DECLARE CURSOR" which # SQLAlchemy doesn't use return "" def order_by_clause(self, select, kw): # MSSQL only allows ORDER BY in subqueries if there is a LIMIT if self.is_subquery() and not select._limit: # avoid processing the order by clause if we won't end up # using it, because we don't want all the bind params tacked # onto the positional list if that is what the dbapi requires return "" order_by = self.process(select._order_by_clause, kw) if order_by: return " ORDER BY " + order_by else: return "" def update_from_clause( self, update_stmt, from_table, extra_froms, from_hints, kw ): """Render the UPDATE..FROM clause specific to MSSQL. In MSSQL, if the UPDATE statement involves an alias of the table to be updated, then the table itself must be added to the FROM list as well. Otherwise, it is optional. Here, we add it regardless. """ return "FROM " + ", ".join( t._compiler_dispatch(self, asfrom=True, fromhints=from_hints, kw) for t in [from_table] + extra_froms ) def delete_table_clause(self, delete_stmt, from_table, extra_froms): """If we have extra froms make sure we render any alias as hint.""" ashint = False if extra_froms: ashint = True return from_table._compiler_dispatch( self, asfrom=True, iscrud=True, ashint=ashint ) def delete_extra_from_clause( self, delete_stmt, from_table, extra_froms, from_hints, kw ): """Render the DELETE .. FROM clause specific to MSSQL. Yes, it has the FROM keyword twice. """ return "FROM " + ", ".join( t._compiler_dispatch(self, asfrom=True, fromhints=from_hints, kw) for t in [from_table] + extra_froms ) def visit_empty_set_expr(self, type_): return "SELECT 1 WHERE 1!=1" def visit_is_distinct_from_binary(self, binary, operator, kw): return "NOT EXISTS (SELECT %s INTERSECT SELECT %s)" % ( self.process(binary.left), self.process(binary.right), ) def visit_isnot_distinct_from_binary(self, binary, operator, kw): return "EXISTS (SELECT %s INTERSECT SELECT %s)" % ( self.process(binary.left), self.process(binary.right), ) class MSSQLStrictCompiler(MSSQLCompiler): """A subclass of MSSQLCompiler which disables the usage of bind parameters where not allowed natively by MS-SQL. A dialect may use this compiler on a platform where native binds are used. """ ansi_bind_rules = True def visit_in_op_binary(self, binary, operator, kw): kw["literal_binds"] = True return "%s IN %s" % ( self.process(binary.left, kw), self.process(binary.right, kw), ) def visit_notin_op_binary(self, binary, operator, kw): kw["literal_binds"] = True return "%s NOT IN %s" % ( self.process(binary.left, kw), self.process(binary.right, kw), ) def render_literal_value(self, value, type_): """ For date and datetime values, convert to a string format acceptable to MSSQL. That seems to be the so-called ODBC canonical date format which looks like this: yyyy-mm-dd hh:mi:ss.mmm(24h) For other data types, call the base class implementation. """ # datetime and date are both subclasses of datetime.date if issubclass(type(value), datetime.date): # SQL Server wants single quotes around the date string. return "'" + str(value) + "'" else: return super(MSSQLStrictCompiler, self).render_literal_value( value, type_ ) class MSDDLCompiler(compiler.DDLCompiler): def get_column_specification(self, column, kwargs): colspec = self.preparer.format_column(column) # type is not accepted in a computed column if column.computed is not None: colspec += " " + self.process(column.computed) else: colspec += " " + self.dialect.type_compiler.process( column.type, type_expression=column ) if column.nullable is not None: if ( not column.nullable or column.primary_key or isinstance(column.default, sa_schema.Sequence) or column.autoincrement is True ): colspec += " NOT NULL" elif column.computed is None: # don't specify "NULL" for computed columns colspec += " NULL" if column.table is None: raise exc.CompileError( "mssql requires Table-bound columns " "in order to generate DDL" ) # install an IDENTITY Sequence if we either a sequence or an implicit # IDENTITY column if isinstance(column.default, sa_schema.Sequence): if ( column.default.start is not None or column.default.increment is not None or column is not column.table._autoincrement_column ): util.warn_deprecated( "Use of Sequence with SQL Server in order to affect the " "parameters of the IDENTITY value is deprecated, as " "Sequence " "will correspond to an actual SQL Server " "CREATE SEQUENCE in " "a future release. Please use the mssql_identity_start " "and mssql_identity_increment parameters." ) if column.default.start == 0: start = 0 else: start = column.default.start or 1 colspec += " IDENTITY(%s,%s)" % ( start, column.default.increment or 1, ) elif ( column is column.table._autoincrement_column or column.autoincrement is True ): start = column.dialect_options["mssql"]["identity_start"] increment = column.dialect_options["mssql"]["identity_increment"] colspec += " IDENTITY(%s,%s)" % (start, increment) else: default = self.get_column_default_string(column) if default is not None: colspec += " DEFAULT " + default return colspec def visit_create_index(self, create, include_schema=False): index = create.element self._verify_index_table(index) preparer = self.preparer text = "CREATE " if index.unique: text += "UNIQUE " # handle clustering option clustered = index.dialect_options["mssql"]["clustered"] if clustered is not None: if clustered: text += "CLUSTERED " else: text += "NONCLUSTERED " text += "INDEX %s ON %s (%s)" % ( self._prepared_index_name(index, include_schema=include_schema), preparer.format_table(index.table), ", ".join( self.sql_compiler.process( expr, include_table=False, literal_binds=True ) for expr in index.expressions ), ) # handle other included columns if index.dialect_options["mssql"]["include"]: inclusions = [ index.table.c[col] if isinstance(col, util.string_types) else col for col in index.dialect_options["mssql"]["include"] ] text += " INCLUDE (%s)" % ", ".join( [preparer.quote(c.name) for c in inclusions] ) whereclause = index.dialect_options["mssql"]["where"] if whereclause is not None: where_compiled = self.sql_compiler.process( whereclause, include_table=False, literal_binds=True ) text += " WHERE " + where_compiled return text def visit_drop_index(self, drop): return "\nDROP INDEX %s ON %s" % ( self._prepared_index_name(drop.element, include_schema=False), self.preparer.format_table(drop.element.table), ) def visit_primary_key_constraint(self, constraint): if len(constraint) == 0: return "" text = "" if constraint.name is not None: text += "CONSTRAINT %s " % self.preparer.format_constraint( constraint ) text += "PRIMARY KEY " clustered = constraint.dialect_options["mssql"]["clustered"] if clustered is not None: if clustered: text += "CLUSTERED " else: text += "NONCLUSTERED " text += "(%s)" % ", ".join( self.preparer.quote(c.name) for c in constraint ) text += self.define_constraint_deferrability(constraint) return text def visit_unique_constraint(self, constraint): if len(constraint) == 0: return "" text = "" if constraint.name is not None: formatted_name = self.preparer.format_constraint(constraint) if formatted_name is not None: text += "CONSTRAINT %s " % formatted_name text += "UNIQUE " clustered = constraint.dialect_options["mssql"]["clustered"] if clustered is not None: if clustered: text += "CLUSTERED " else: text += "NONCLUSTERED " text += "(%s)" % ", ".join( self.preparer.quote(c.name) for c in constraint ) text += self.define_constraint_deferrability(constraint) return text def visit_computed_column(self, generated): text = "AS (%s)" % self.sql_compiler.process( generated.sqltext, include_table=False, literal_binds=True ) # explicitly check for True\|False since None means server default if generated.persisted is True: text += " PERSISTED" return text class MSIdentifierPreparer(compiler.IdentifierPreparer): reserved_words = RESERVED_WORDS def __init__(self, dialect): super(MSIdentifierPreparer, self).__init__( dialect, initial_quote="[", final_quote="]", quote_case_sensitive_collations=False, ) def _escape_identifier(self, value): return value.replace("]", "]]") def _unescape_identifier(self, value): return value.replace("]]", "]") def quote_schema(self, schema, force=None): """Prepare a quoted table and schema name.""" # need to re-implement the deprecation warning entirely if force is not None: # not using the util.deprecated_params() decorator in this # case because of the additional function call overhead on this # very performance-critical spot. util.warn_deprecated( "The IdentifierPreparer.quote_schema.force parameter is " "deprecated and will be removed in a future release. This " "flag has no effect on the behavior of the " "IdentifierPreparer.quote method; please refer to " "quoted_name()." ) dbname, owner = _schema_elements(schema) if dbname: result = "%s.%s" % (self.quote(dbname), self.quote(owner)) elif owner: result = self.quote(owner) else: result = "" return result def _db_plus_owner_listing(fn): def wrap(dialect, connection, schema=None, kw): dbname, owner = _owner_plus_db(dialect, schema) return _switch_db( dbname, connection, fn, dialect, connection, dbname, owner, schema, kw ) return update_wrapper(wrap, fn) def _db_plus_owner(fn): def wrap(dialect, connection, tablename, schema=None, kw): dbname, owner = _owner_plus_db(dialect, schema) return _switch_db( dbname, connection, fn, dialect, connection, tablename, dbname, owner, schema, *kw ) return update_wrapper(wrap, fn) def _switch_db(dbname, connection, fn, arg, *kw): if dbname: current_db = connection.scalar("select db_name()") if current_db != dbname: connection.execute( "use %s" % connection.dialect.identifier_preparer.quote(dbname) ) try: return fn(arg, *kw) finally: if dbname and current_db != dbname: connection.execute( "use %s" % connection.dialect.identifier_preparer.quote(current_db) ) def _owner_plus_db(dialect, schema): if not schema: return None, dialect.default_schema_name elif "." in schema: return _schema_elements(schema) else: return None, schema _memoized_schema = util.LRUCache() def _schema_elements(schema): if isinstance(schema, quoted_name) and schema.quote: return None, schema if schema in _memoized_schema: return _memoized_schema[schema] # tests for this function are in: # test/dialect/mssql/test_reflection.py -> # OwnerPlusDBTest.test_owner_database_pairs # test/dialect/mssql/test_compiler.py -> test_force_schema_ # test/dialect/mssql/test_compiler.py -> test_schema_many_tokens_* # push = [] symbol = "" bracket = False has_brackets = False for token in re.split(r"(\[\|\]\|\.)", schema): if not token: continue if token == "[": bracket = True has_brackets = True elif token == "]": bracket = False elif not bracket and token == ".": if has_brackets: push.append("[%s]" % symbol) else: push.append(symbol) symbol = "" has_brackets = False else: symbol += token if symbol: push.append(symbol) if len(push) > 1: dbname, owner = ".".join(push[0:-1]), push[-1] # test for internal brackets if re.match(r".\].\[.", dbname[1:-1]): dbname = quoted_name(dbname, quote=False) else: dbname = dbname.lstrip("[").rstrip("]") elif len(push): dbname, owner = None, push[0] else: dbname, owner = None, None _memoized_schema[schema] = dbname, owner return dbname, owner class MSDialect(default.DefaultDialect): name = "mssql" supports_default_values = True supports_empty_insert = False execution_ctx_cls = MSExecutionContext use_scope_identity = True max_identifier_length = 128 schema_name = "dbo" colspecs = { sqltypes.DateTime: _MSDateTime, sqltypes.Date: _MSDate, sqltypes.Time: TIME, sqltypes.Unicode: _MSUnicode, sqltypes.UnicodeText: _MSUnicodeText, } engine_config_types = default.DefaultDialect.engine_config_types.union( [("legacy_schema_aliasing", util.asbool)] ) ischema_names = ischema_names supports_native_boolean = False non_native_boolean_check_constraint = False supports_unicode_binds = True postfetch_lastrowid = True _supports_nvarchar_max = False server_version_info = () statement_compiler = MSSQLCompiler ddl_compiler = MSDDLCompiler type_compiler = MSTypeCompiler preparer = MSIdentifierPreparer construct_arguments = [ (sa_schema.PrimaryKeyConstraint, {"clustered": None}), (sa_schema.UniqueConstraint, {"clustered": None}), (sa_schema.Index, {"clustered": None, "include": None, "where": None}), (sa_schema.Column, {"identity_start": 1, "identity_increment": 1}), ] def __init__( self, query_timeout=None, use_scope_identity=True, schema_name="dbo", isolation_level=None, deprecate_large_types=None, legacy_schema_aliasing=False, opts ): self.query_timeout = int(query_timeout or 0) self.schema_name = schema_name self.use_scope_identity = use_scope_identity self.deprecate_large_types = deprecate_large_types self.legacy_schema_aliasing = legacy_schema_aliasing super(MSDialect, self).__init__(opts) self.isolation_level = isolation_level def do_savepoint(self, connection, name): # give the DBAPI a push connection.execute("IF @@TRANCOUNT = 0 BEGIN TRANSACTION") super(MSDialect, self).do_savepoint(connection, name) def do_release_savepoint(self, connection, name): # SQL Server does not support RELEASE SAVEPOINT pass _isolation_lookup = set( [ "SERIALIZABLE", "READ UNCOMMITTED", "READ COMMITTED", "REPEATABLE READ", "SNAPSHOT", ] ) def set_isolation_level(self, connection, level): level = level.replace("_", " ") if level not in self._isolation_lookup: raise exc.ArgumentError( "Invalid value '%s' for isolation_level. " "Valid isolation levels for %s are %s" % (level, self.name, ", ".join(self._isolation_lookup)) ) cursor = connection.cursor() cursor.execute("SET TRANSACTION ISOLATION LEVEL %s" % level) cursor.close() if level == "SNAPSHOT": connection.commit() def get_isolation_level(self, connection): if self.server_version_info < MS_2005_VERSION: raise NotImplementedError( "Can't fetch isolation level prior to SQL Server 2005" ) last_error = None views = ("sys.dm_exec_sessions", "sys.dm_pdw_nodes_exec_sessions") for view in views: cursor = connection.cursor() try: cursor.execute( """ SELECT CASE transaction_isolation_level WHEN 0 THEN NULL WHEN 1 THEN 'READ UNCOMMITTED' WHEN 2 THEN 'READ COMMITTED' WHEN 3 THEN 'REPEATABLE READ' WHEN 4 THEN 'SERIALIZABLE' WHEN 5 THEN 'SNAPSHOT' END AS TRANSACTION_ISOLATION_LEVEL FROM %s where session_id = @@SPID """ % view ) val = cursor.fetchone()[0] except self.dbapi.Error as err: # Python3 scoping rules last_error = err continue else: return val.upper() finally: cursor.close() else: # note that the NotImplementedError is caught by # DefaultDialect, so the warning here is all that displays util.warn( "Could not fetch transaction isolation level, " "tried views: %s; final error was: %s" % (views, last_error) ) raise NotImplementedError( "Can't fetch isolation level on this particular " "SQL Server version. tried views: %s; final error was: %s" % (views, last_error) ) def initialize(self, connection): super(MSDialect, self).initialize(connection) self._setup_version_attributes() self._setup_supports_nvarchar_max(connection) def on_connect(self): if self.isolation_level is not None: def connect(conn): self.set_isolation_level(conn, self.isolation_level) return connect else: return None def _setup_version_attributes(self): if self.server_version_info[0] not in list(range(8, 17)): util.warn( "Unrecognized server version info '%s'. Some SQL Server " "features may not function properly." % ".".join(str(x) for x in self.server_version_info) ) if ( self.server_version_info >= MS_2005_VERSION and "implicit_returning" not in self.__dict__ ): self.implicit_returning = True if self.server_version_info >= MS_2008_VERSION: self.supports_multivalues_insert = True if self.deprecate_large_types is None: self.deprecate_large_types = ( self.server_version_info >= MS_2012_VERSION ) def _setup_supports_nvarchar_max(self, connection): try: connection.scalar( sql.text("SELECT CAST('test max support' AS NVARCHAR(max))") ) except exc.DBAPIError: self._supports_nvarchar_max = False else: self._supports_nvarchar_max = True def _get_default_schema_name(self, connection): if self.server_version_info < MS_2005_VERSION: return self.schema_name else: query = sql.text("SELECT schema_name()") default_schema_name = connection.scalar(query) if default_schema_name is not None: # guard against the case where the default_schema_name is being # fed back into a table reflection function. return quoted_name(default_schema_name, quote=True) else: return self.schema_name @_db_plus_owner def has_table(self, connection, tablename, dbname, owner, schema): columns = ischema.columns whereclause = columns.c.table_name == tablename if owner: whereclause = sql.and_( whereclause, columns.c.table_schema == owner ) s = sql.select([columns], whereclause) c = connection.execute(s) return c.first() is not None @reflection.cache def get_schema_names(self, connection, kw): s = sql.select( [ischema.schemata.c.schema_name], order_by=[ischema.schemata.c.schema_name], ) schema_names = [r[0] for r in connection.execute(s)] return schema_names @reflection.cache @_db_plus_owner_listing def get_table_names(self, connection, dbname, owner, schema, kw): tables = ischema.tables s = sql.select( [tables.c.table_name], sql.and_( tables.c.table_schema == owner, tables.c.table_type == "BASE TABLE", ), order_by=[tables.c.table_name], ) table_names = [r[0] for r in connection.execute(s)] return table_names @reflection.cache @_db_plus_owner_listing def get_view_names(self, connection, dbname, owner, schema, kw): tables = ischema.tables s = sql.select( [tables.c.table_name], sql.and_( tables.c.table_schema == owner, tables.c.table_type == "VIEW" ), order_by=[tables.c.table_name], ) view_names = [r[0] for r in connection.execute(s)] return view_names @reflection.cache @_db_plus_owner def get_indexes(self, connection, tablename, dbname, owner, schema, kw): # using system catalogs, don't support index reflection # below MS 2005 if self.server_version_info < MS_2005_VERSION: return [] rp = connection.execute( sql.text( "select ind.index_id, ind.is_unique, ind.name " "from sys.indexes as ind join sys.tables as tab on " "ind.object_id=tab.object_id " "join sys.schemas as sch on sch.schema_id=tab.schema_id " "where tab.name = :tabname " "and sch.name=:schname " "and ind.is_primary_key=0 and ind.type != 0" ) .bindparams( sql.bindparam("tabname", tablename, ischema.CoerceUnicode()), sql.bindparam("schname", owner, ischema.CoerceUnicode()), ) .columns(name=sqltypes.Unicode()) ) indexes = {} for row in rp: indexes[row["index_id"]] = { "name": row["name"], "unique": row["is_unique"] == 1, "column_names": [], } rp = connection.execute( sql.text( "select ind_col.index_id, ind_col.object_id, col.name " "from sys.columns as col " "join sys.tables as tab on tab.object_id=col.object_id " "join sys.index_columns as ind_col on " "(ind_col.column_id=col.column_id and " "ind_col.object_id=tab.object_id) " "join sys.schemas as sch on sch.schema_id=tab.schema_id " "where tab.name=:tabname " "and sch.name=:schname" ) .bindparams( sql.bindparam("tabname", tablename, ischema.CoerceUnicode()), sql.bindparam("schname", owner, ischema.CoerceUnicode()), ) .columns(name=sqltypes.Unicode()) ) for row in rp: if row["index_id"] in indexes: indexes[row["index_id"]]["column_names"].append(row["name"]) return list(indexes.values()) @reflection.cache @_db_plus_owner def get_view_definition( self, connection, viewname, dbname, owner, schema, kw ): rp = connection.execute( sql.text( "select definition from sys.sql_modules as mod, " "sys.views as views, " "sys.schemas as sch" " where " "mod.object_id=views.object_id and " "views.schema_id=sch.schema_id and " "views.name=:viewname and sch.name=:schname" ).bindparams( sql.bindparam("viewname", viewname, ischema.CoerceUnicode()), sql.bindparam("schname", owner, ischema.CoerceUnicode()), ) ) if rp: view_def = rp.scalar() return view_def @reflection.cache @_db_plus_owner def get_columns(self, connection, tablename, dbname, owner, schema, kw): # Get base columns columns = ischema.columns computed_cols = ischema.computed_columns if owner: whereclause = sql.and_( columns.c.table_name == tablename, columns.c.table_schema == owner, ) table_fullname = "%s.%s" % (owner, tablename) full_name = columns.c.table_schema + "." + columns.c.table_name join_on = computed_cols.c.object_id == func.object_id(full_name) else: whereclause = columns.c.table_name == tablename table_fullname = tablename join_on = computed_cols.c.object_id == func.object_id( columns.c.table_name ) join_on = sql.and_( join_on, columns.c.column_name == computed_cols.c.name ) join = columns.join(computed_cols, onclause=join_on, isouter=True) if self._supports_nvarchar_max: computed_definition = computed_cols.c.definition else: # tds_version 4.2 does not support NVARCHAR(MAX) computed_definition = sql.cast( computed_cols.c.definition, NVARCHAR(4000) ) s = sql.select( [columns, computed_definition, computed_cols.c.is_persisted], whereclause, from_obj=join, order_by=[columns.c.ordinal_position], ) c = connection.execute(s) cols = [] while True: row = c.fetchone() if row is None: break name = row[columns.c.column_name] type_ = row[columns.c.data_type] nullable = row[columns.c.is_nullable] == "YES" charlen = row[columns.c.character_maximum_length] numericprec = row[columns.c.numeric_precision] numericscale = row[columns.c.numeric_scale] default = row[columns.c.column_default] collation = row[columns.c.collation_name] definition = row[computed_definition] is_persisted = row[computed_cols.c.is_persisted] coltype = self.ischema_names.get(type_, None) kwargs = {} if coltype in ( MSString, MSChar, MSNVarchar, MSNChar, MSText, MSNText, MSBinary, MSVarBinary, sqltypes.LargeBinary, ): if charlen == -1: charlen = None kwargs["length"] = charlen if collation: kwargs["collation"] = collation if coltype is None: util.warn( "Did not recognize type '%s' of column '%s'" % (type_, name) ) coltype = sqltypes.NULLTYPE else: if issubclass(coltype, sqltypes.Numeric): kwargs["precision"] = numericprec if not issubclass(coltype, sqltypes.Float): kwargs["scale"] = numericscale coltype = coltype(kwargs) cdict = { "name": name, "type": coltype, "nullable": nullable, "default": default, "autoincrement": False, } if definition is not None and is_persisted is not None: cdict["computed"] = { "sqltext": definition, "persisted": is_persisted, } cols.append(cdict) # autoincrement and identity colmap = {} for col in cols: colmap[col["name"]] = col # We also run an sp_columns to check for identity columns: cursor = connection.execute( sql.text( "EXEC sp_columns @table_name = :table_name, " "@table_owner = :table_owner", ), {"table_name": tablename, "table_owner": owner}, ) ic = None while True: row = cursor.fetchone() if row is None: break (col_name, type_name) = row[3], row[5] if type_name.endswith("identity") and col_name in colmap: ic = col_name colmap[col_name]["autoincrement"] = True colmap[col_name]["dialect_options"] = { "mssql_identity_start": 1, "mssql_identity_increment": 1, } break cursor.close() if ic is not None and self.server_version_info >= MS_2005_VERSION: table_fullname = "%s.%s" % (owner, tablename) cursor = connection.execute( "select ident_seed('%s'), ident_incr('%s')" % (table_fullname, table_fullname) ) row = cursor.first() if row is not None and row[0] is not None: colmap[ic]["dialect_options"].update( { "mssql_identity_start": int(row[0]), "mssql_identity_increment": int(row[1]), } ) return cols @reflection.cache @_db_plus_owner def get_pk_constraint( self, connection, tablename, dbname, owner, schema, kw ): pkeys = [] TC = ischema.constraints C = ischema.key_constraints.alias("C") # Primary key constraints s = sql.select( [C.c.column_name, TC.c.constraint_type, C.c.constraint_name], sql.and_( TC.c.constraint_name == C.c.constraint_name, TC.c.table_schema == C.c.table_schema, C.c.table_name == tablename, C.c.table_schema == owner, ), ).order_by(TC.c.constraint_name, C.c.ordinal_position) c = connection.execute(s) constraint_name = None for row in c: if "PRIMARY" in row[TC.c.constraint_type.name]: pkeys.append(row[0]) if constraint_name is None: constraint_name = row[C.c.constraint_name.name] return {"constrained_columns": pkeys, "name": constraint_name} @reflection.cache @_db_plus_owner def get_foreign_keys( self, connection, tablename, dbname, owner, schema, *kw ): RR = ischema.ref_constraints C = ischema.key_constraints.alias("C") R = ischema.key_constraints.alias("R") # Foreign key constraints s = sql.select( [ C.c.column_name, R.c.table_schema, R.c.table_name, R.c.column_name, RR.c.constraint_name, RR.c.match_option, RR.c.update_rule, RR.c.delete_rule, ], sql.and_( C.c.table_name == tablename, C.c.table_schema == owner, RR.c.constraint_schema == C.c.table_schema, C.c.constraint_name == RR.c.constraint_name, R.c.constraint_name == RR.c.unique_constraint_name, R.c.constraint_schema == RR.c.unique_constraint_schema, C.c.ordinal_position == R.c.ordinal_position, ), order_by=[RR.c.constraint_name, R.c.ordinal_position], ) # group rows by constraint ID, to handle multi-column FKs fkeys = [] def fkey_rec(): return { "name": None, "constrained_columns": [], "referred_schema": None, "referred_table": None, "referred_columns": [], } fkeys = util.defaultdict(fkey_rec) for r in connection.execute(s).fetchall(): scol, rschema, rtbl, rcol, rfknm, fkmatch, fkuprule, fkdelrule = r rec = fkeys[rfknm] rec["name"] = rfknm if not rec["referred_table"]: rec["referred_table"] = rtbl if schema is not None or owner != rschema: if dbname: rschema = dbname + "." + rschema rec["referred_schema"] = rschema local_cols, remote_cols = ( rec["constrained_columns"], rec["referred_columns"], ) local_cols.append(scol) remote_cols.append(rcol) return list(fkeys.values())	89.17 KB	2026-01-20 12:58
📄 information_schema.py # mssql/information_schema.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php # TODO: should be using the sys. catalog with SQL Server, not information # schema from ... import cast from ... import Column from ... import MetaData from ... import Table from ... import util from ...ext.compiler import compiles from ...sql import expression from ...types import Boolean from ...types import Integer from ...types import String from ...types import TypeDecorator from ...types import Unicode ischema = MetaData() class CoerceUnicode(TypeDecorator): impl = Unicode def process_bind_param(self, value, dialect): if util.py2k and isinstance(value, util.binary_type): value = value.decode(dialect.encoding) return value def bind_expression(self, bindvalue): return _cast_on_2005(bindvalue) class _cast_on_2005(expression.ColumnElement): def __init__(self, bindvalue): self.bindvalue = bindvalue @compiles(_cast_on_2005) def _compile(element, compiler, kw): from . import base if ( compiler.dialect.server_version_info is None or compiler.dialect.server_version_info < base.MS_2005_VERSION ): return compiler.process(element.bindvalue, kw) else: return compiler.process(cast(element.bindvalue, Unicode), **kw) schemata = Table( "SCHEMATA", ischema, Column("CATALOG_NAME", CoerceUnicode, key="catalog_name"), Column("SCHEMA_NAME", CoerceUnicode, key="schema_name"), Column("SCHEMA_OWNER", CoerceUnicode, key="schema_owner"), schema="INFORMATION_SCHEMA", ) tables = Table( "TABLES", ischema, Column("TABLE_CATALOG", CoerceUnicode, key="table_catalog"), Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"), Column("TABLE_NAME", CoerceUnicode, key="table_name"), Column("TABLE_TYPE", CoerceUnicode, key="table_type"), schema="INFORMATION_SCHEMA", ) columns = Table( "COLUMNS", ischema, Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"), Column("TABLE_NAME", CoerceUnicode, key="table_name"), Column("COLUMN_NAME", CoerceUnicode, key="column_name"), Column("IS_NULLABLE", Integer, key="is_nullable"), Column("DATA_TYPE", String, key="data_type"), Column("ORDINAL_POSITION", Integer, key="ordinal_position"), Column( "CHARACTER_MAXIMUM_LENGTH", Integer, key="character_maximum_length" ), Column("NUMERIC_PRECISION", Integer, key="numeric_precision"), Column("NUMERIC_SCALE", Integer, key="numeric_scale"), Column("COLUMN_DEFAULT", Integer, key="column_default"), Column("COLLATION_NAME", String, key="collation_name"), schema="INFORMATION_SCHEMA", ) constraints = Table( "TABLE_CONSTRAINTS", ischema, Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"), Column("TABLE_NAME", CoerceUnicode, key="table_name"), Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"), Column("CONSTRAINT_TYPE", CoerceUnicode, key="constraint_type"), schema="INFORMATION_SCHEMA", ) column_constraints = Table( "CONSTRAINT_COLUMN_USAGE", ischema, Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"), Column("TABLE_NAME", CoerceUnicode, key="table_name"), Column("COLUMN_NAME", CoerceUnicode, key="column_name"), Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"), schema="INFORMATION_SCHEMA", ) key_constraints = Table( "KEY_COLUMN_USAGE", ischema, Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"), Column("TABLE_NAME", CoerceUnicode, key="table_name"), Column("COLUMN_NAME", CoerceUnicode, key="column_name"), Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"), Column("CONSTRAINT_SCHEMA", CoerceUnicode, key="constraint_schema"), Column("ORDINAL_POSITION", Integer, key="ordinal_position"), schema="INFORMATION_SCHEMA", ) ref_constraints = Table( "REFERENTIAL_CONSTRAINTS", ischema, Column("CONSTRAINT_CATALOG", CoerceUnicode, key="constraint_catalog"), Column("CONSTRAINT_SCHEMA", CoerceUnicode, key="constraint_schema"), Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"), # TODO: is CATLOG misspelled ? Column( "UNIQUE_CONSTRAINT_CATLOG", CoerceUnicode, key="unique_constraint_catalog", ), Column( "UNIQUE_CONSTRAINT_SCHEMA", CoerceUnicode, key="unique_constraint_schema", ), Column( "UNIQUE_CONSTRAINT_NAME", CoerceUnicode, key="unique_constraint_name" ), Column("MATCH_OPTION", String, key="match_option"), Column("UPDATE_RULE", String, key="update_rule"), Column("DELETE_RULE", String, key="delete_rule"), schema="INFORMATION_SCHEMA", ) views = Table( "VIEWS", ischema, Column("TABLE_CATALOG", CoerceUnicode, key="table_catalog"), Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"), Column("TABLE_NAME", CoerceUnicode, key="table_name"), Column("VIEW_DEFINITION", CoerceUnicode, key="view_definition"), Column("CHECK_OPTION", String, key="check_option"), Column("IS_UPDATABLE", String, key="is_updatable"), schema="INFORMATION_SCHEMA", ) computed_columns = Table( "computed_columns", ischema, Column("object_id", Integer), Column("name", CoerceUnicode), Column("is_computed", Boolean), Column("is_persisted", Boolean), Column("definition", CoerceUnicode), schema="sys", )	5.51 KB	2026-01-20 12:58
📄 mxodbc.py # mssql/mxodbc.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """ .. dialect:: mssql+mxodbc :name: mxODBC :dbapi: mxodbc :connectstring: mssql+mxodbc://<username>:<password>@<dsnname> :url: http://www.egenix.com/ Execution Modes --------------- mxODBC features two styles of statement execution, using the ``cursor.execute()`` and ``cursor.executedirect()`` methods (the second being an extension to the DBAPI specification). The former makes use of a particular API call specific to the SQL Server Native Client ODBC driver known SQLDescribeParam, while the latter does not. mxODBC apparently only makes repeated use of a single prepared statement when SQLDescribeParam is used. The advantage to prepared statement reuse is one of performance. The disadvantage is that SQLDescribeParam has a limited set of scenarios in which bind parameters are understood, including that they cannot be placed within the argument lists of function calls, anywhere outside the FROM, or even within subqueries within the FROM clause - making the usage of bind parameters within SELECT statements impossible for all but the most simplistic statements. For this reason, the mxODBC dialect uses the "native" mode by default only for INSERT, UPDATE, and DELETE statements, and uses the escaped string mode for all other statements. This behavior can be controlled via :meth:`~sqlalchemy.sql.expression.Executable.execution_options` using the ``native_odbc_execute`` flag with a value of ``True`` or ``False``, where a value of ``True`` will unconditionally use native bind parameters and a value of ``False`` will unconditionally use string-escaped parameters. """ from .base import _MSDate from .base import _MSDateTime from .base import _MSTime from .base import MSDialect from .base import VARBINARY from .pyodbc import _MSNumeric_pyodbc from .pyodbc import MSExecutionContext_pyodbc from ... import types as sqltypes from ...connectors.mxodbc import MxODBCConnector class _MSNumeric_mxodbc(_MSNumeric_pyodbc): """Include pyodbc's numeric processor.""" class _MSDate_mxodbc(_MSDate): def bind_processor(self, dialect): def process(value): if value is not None: return "%s-%s-%s" % (value.year, value.month, value.day) else: return None return process class _MSTime_mxodbc(_MSTime): def bind_processor(self, dialect): def process(value): if value is not None: return "%s:%s:%s" % (value.hour, value.minute, value.second) else: return None return process class _VARBINARY_mxodbc(VARBINARY): """ mxODBC Support for VARBINARY column types. This handles the special case for null VARBINARY values, which maps None values to the mx.ODBC.Manager.BinaryNull symbol. """ def bind_processor(self, dialect): if dialect.dbapi is None: return None DBAPIBinary = dialect.dbapi.Binary def process(value): if value is not None: return DBAPIBinary(value) else: # should pull from mx.ODBC.Manager.BinaryNull return dialect.dbapi.BinaryNull return process class MSExecutionContext_mxodbc(MSExecutionContext_pyodbc): """ The pyodbc execution context is useful for enabling SELECT SCOPE_IDENTITY in cases where OUTPUT clause does not work (tables with insert triggers). """ # todo - investigate whether the pyodbc execution context # is really only being used in cases where OUTPUT # won't work. class MSDialect_mxodbc(MxODBCConnector, MSDialect): # this is only needed if "native ODBC" mode is used, # which is now disabled by default. # statement_compiler = MSSQLStrictCompiler execution_ctx_cls = MSExecutionContext_mxodbc # flag used by _MSNumeric_mxodbc _need_decimal_fix = True colspecs = { sqltypes.Numeric: _MSNumeric_mxodbc, sqltypes.DateTime: _MSDateTime, sqltypes.Date: _MSDate_mxodbc, sqltypes.Time: _MSTime_mxodbc, VARBINARY: _VARBINARY_mxodbc, sqltypes.LargeBinary: _VARBINARY_mxodbc, } def __init__(self, description_encoding=None, params): super(MSDialect_mxodbc, self).__init__(params) self.description_encoding = description_encoding dialect = MSDialect_mxodbc	4.5 KB	2026-01-20 12:58
📄 provision.py from ... import create_engine from ... import exc from ...testing.provision import create_db from ...testing.provision import drop_db from ...testing.provision import log from ...testing.provision import run_reap_dbs from ...testing.provision import update_db_opts @update_db_opts.for_db("mssql") def _mssql_update_db_opts(db_url, db_opts): db_opts["legacy_schema_aliasing"] = False @create_db.for_db("mssql") def _mssql_create_db(cfg, eng, ident): with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn: conn.execute("create database %s" % ident) conn.execute( "ALTER DATABASE %s SET ALLOW_SNAPSHOT_ISOLATION ON" % ident ) conn.execute( "ALTER DATABASE %s SET READ_COMMITTED_SNAPSHOT ON" % ident ) conn.execute("use %s" % ident) conn.execute("create schema test_schema") conn.execute("create schema test_schema_2") @drop_db.for_db("mssql") def _mssql_drop_db(cfg, eng, ident): with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn: _mssql_drop_ignore(conn, ident) def _mssql_drop_ignore(conn, ident): try: # typically when this happens, we can't KILL the session anyway, # so let the cleanup process drop the DBs # for row in conn.execute( # "select session_id from sys.dm_exec_sessions " # "where database_id=db_id('%s')" % ident): # log.info("killing SQL server session %s", row['session_id']) # conn.execute("kill %s" % row['session_id']) conn.execute("drop database %s" % ident) log.info("Reaped db: %s", ident) return True except exc.DatabaseError as err: log.warning("couldn't drop db: %s", err) return False @run_reap_dbs.for_db("mssql") def _reap_mssql_dbs(url, idents): log.info("db reaper connecting to %r", url) eng = create_engine(url) with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn: log.info("identifiers in file: %s", ", ".join(idents)) to_reap = conn.execute( "select d.name from sys.databases as d where name " "like 'TEST_%' and not exists (select session_id " "from sys.dm_exec_sessions " "where database_id=d.database_id)" ) all_names = {dbname.lower() for (dbname,) in to_reap} to_drop = set() for name in all_names: if name in idents: to_drop.add(name) dropped = total = 0 for total, dbname in enumerate(to_drop, 1): if _mssql_drop_ignore(conn, dbname): dropped += 1 log.info( "Dropped %d out of %d stale databases detected", dropped, total )	2.72 KB	2026-01-20 12:58
📄 pymssql.py # mssql/pymssql.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """ .. dialect:: mssql+pymssql :name: pymssql :dbapi: pymssql :connectstring: mssql+pymssql://<username>:<password>@<freetds_name>/?charset=utf8 pymssql is a Python module that provides a Python DBAPI interface around `FreeTDS <http://www.freetds.org/>`_. .. note:: pymssql is currently not included in SQLAlchemy's continuous integration (CI) testing. Modern versions of this driver worked very well with SQL Server and FreeTDS from Linux and were highly recommended. However, pymssql is currently unmaintained and has fallen behind the progress of the Microsoft ODBC driver in its support for newer features of SQL Server. The latest official release of pymssql at the time of this document is version 2.1.4 (August, 2018) and it lacks support for: 1. table-valued parameters (TVPs), 2. ``datetimeoffset`` columns using timezone-aware ``datetime`` objects (values are sent and retrieved as strings), and 3. encrypted connections (e.g., to Azure SQL), when pymssql is installed from the pre-built wheels. Support for encrypted connections requires building pymssql from source, which can be a nuisance, especially under Windows. The above features are all supported by mssql+pyodbc when using Microsoft's ODBC Driver for SQL Server (msodbcsql), which is now available for Windows, (several flavors of) Linux, and macOS. """ # noqa import re from .base import MSDialect from .base import MSIdentifierPreparer from ... import processors from ... import types as sqltypes from ... import util class _MSNumeric_pymssql(sqltypes.Numeric): def result_processor(self, dialect, type_): if not self.asdecimal: return processors.to_float else: return sqltypes.Numeric.result_processor(self, dialect, type_) class MSIdentifierPreparer_pymssql(MSIdentifierPreparer): def __init__(self, dialect): super(MSIdentifierPreparer_pymssql, self).__init__(dialect) # pymssql has the very unusual behavior that it uses pyformat # yet does not require that percent signs be doubled self._double_percents = False class MSDialect_pymssql(MSDialect): supports_native_decimal = True driver = "pymssql" preparer = MSIdentifierPreparer_pymssql colspecs = util.update_copy( MSDialect.colspecs, {sqltypes.Numeric: _MSNumeric_pymssql, sqltypes.Float: sqltypes.Float}, ) @classmethod def dbapi(cls): module = __import__("pymssql") # pymmsql < 2.1.1 doesn't have a Binary method. we use string client_ver = tuple(int(x) for x in module.__version__.split(".")) if client_ver < (2, 1, 1): # TODO: monkeypatching here is less than ideal module.Binary = lambda x: x if hasattr(x, "decode") else str(x) if client_ver < (1,): util.warn( "The pymssql dialect expects at least " "the 1.0 series of the pymssql DBAPI." ) return module def _get_server_version_info(self, connection): vers = connection.scalar("select @@version") m = re.match(r"Microsoft .*? - (\d+).(\d+).(\d+).(\d+)", vers) if m: return tuple(int(x) for x in m.group(1, 2, 3, 4)) else: return None def create_connect_args(self, url): opts = url.translate_connect_args(username="user") opts.update(url.query) port = opts.pop("port", None) if port and "host" in opts: opts["host"] = "%s:%s" % (opts["host"], port) return [[], opts] def is_disconnect(self, e, connection, cursor): for msg in ( "Adaptive Server connection timed out", "Net-Lib error during Connection reset by peer", "message 20003", # connection timeout "Error 10054", "Not connected to any MS SQL server", "Connection is closed", "message 20006", # Write to the server failed "message 20017", # Unexpected EOF from the server "message 20047", # DBPROCESS is dead or not enabled ): if msg in str(e): return True else: return False def set_isolation_level(self, connection, level): if level == "AUTOCOMMIT": connection.autocommit(True) else: connection.autocommit(False) super(MSDialect_pymssql, self).set_isolation_level( connection, level ) dialect = MSDialect_pymssql	4.67 KB	2026-01-20 12:58
📄 pyodbc.py # mssql/pyodbc.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php r""" .. dialect:: mssql+pyodbc :name: PyODBC :dbapi: pyodbc :connectstring: mssql+pyodbc://<username>:<password>@<dsnname> :url: http://pypi.python.org/pypi/pyodbc/ Connecting to PyODBC -------------------- The URL here is to be translated to PyODBC connection strings, as detailed in `ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_. DSN Connections ^^^^^^^^^^^^^^^ A DSN connection in ODBC means that a pre-existing ODBC datasource is configured on the client machine. The application then specifies the name of this datasource, which encompasses details such as the specific ODBC driver in use as well as the network address of the database. Assuming a datasource is configured on the client, a basic DSN-based connection looks like:: engine = create_engine("mssql+pyodbc://scott:tiger@some_dsn") Which above, will pass the following connection string to PyODBC:: dsn=mydsn;UID=user;PWD=pass If the username and password are omitted, the DSN form will also add the ``Trusted_Connection=yes`` directive to the ODBC string. Hostname Connections ^^^^^^^^^^^^^^^^^^^^ Hostname-based connections are also supported by pyodbc. These are often easier to use than a DSN and have the additional advantage that the specific database name to connect towards may be specified locally in the URL, rather than it being fixed as part of a datasource configuration. When using a hostname connection, the driver name must also be specified in the query parameters of the URL. As these names usually have spaces in them, the name must be URL encoded which means using plus signs for spaces:: engine = create_engine("mssql+pyodbc://scott:tiger@myhost:port/databasename?driver=SQL+Server+Native+Client+10.0") Other keywords interpreted by the Pyodbc dialect to be passed to ``pyodbc.connect()`` in both the DSN and hostname cases include: ``odbc_autotranslate``, ``ansi``, ``unicode_results``, ``autocommit``, ``authentication`` (e.g., ``authentication=ActiveDirectoryIntegrated``). Note that in order for the dialect to recognize these keywords (including the ``driver`` keyword above) they must be all lowercase. Pass through exact Pyodbc string ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ A PyODBC connection string can also be sent in pyodbc's format directly, as specified in `ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_ into the driver using the parameter ``odbc_connect``. The delimeters must be URL encoded, as illustrated below using ``urllib.parse.quote_plus``:: import urllib params = urllib.parse.quote_plus("DRIVER={SQL Server Native Client 10.0};SERVER=dagger;DATABASE=test;UID=user;PWD=password") engine = create_engine("mssql+pyodbc:///?odbc_connect=%s" % params) Pyodbc Pooling / connection close behavior ------------------------------------------ PyODBC uses internal `pooling <https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ by default, which means connections will be longer lived than they are within SQLAlchemy itself. As SQLAlchemy has its own pooling behavior, it is often preferable to disable this behavior. This behavior can only be disabled globally at the PyODBC module level, before any connections are made:: import pyodbc pyodbc.pooling = False # don't use the engine before pooling is set to False engine = create_engine("mssql+pyodbc://user:pass@dsn") If this variable is left at its default value of ``True``, the application will continue to maintain active database connections, even when the SQLAlchemy engine itself fully discards a connection or if the engine is disposed. .. seealso:: `pooling <https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ - in the PyODBC documentation. Driver / Unicode Support ------------------------- PyODBC works best with Microsoft ODBC drivers, particularly in the area of Unicode support on both Python 2 and Python 3. Using the FreeTDS ODBC drivers on Linux or OSX with PyODBC is not recommended; there have been historically many Unicode-related issues in this area, including before Microsoft offered ODBC drivers for Linux and OSX. Now that Microsoft offers drivers for all platforms, for PyODBC support these are recommended. FreeTDS remains relevant for non-ODBC drivers such as pymssql where it works very well. Rowcount Support ---------------- Pyodbc only has partial support for rowcount. See the notes at :ref:`mssql_rowcount_versioning` for important notes when using ORM versioning. .. _mssql_pyodbc_fastexecutemany: Fast Executemany Mode --------------------- The Pyodbc driver has added support for a "fast executemany" mode of execution which greatly reduces round trips for a DBAPI ``executemany()`` call when using Microsoft ODBC drivers, for limited size batches that fit in memory. The feature is enabled by setting the flag ``.fast_executemany`` on the DBAPI cursor when an executemany call is to be used. The SQLAlchemy pyodbc SQL Server dialect supports setting this flag automatically when the ``.fast_executemany`` flag is passed to :func:`_sa.create_engine` ; note that the ODBC driver must be the Microsoft driver in order to use this flag:: engine = create_engine( "mssql+pyodbc://scott:tiger@mssql2017:1433/test?driver=ODBC+Driver+13+for+SQL+Server", fast_executemany=True) .. warning:: The pyodbc fast_executemany mode buffers all rows in memory and is not compatible with very large batches of data. A future version of SQLAlchemy may support this flag as a per-execution option instead. .. versionadded:: 1.3 .. seealso:: `fast executemany <https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany>`_ - on github """ # noqa import datetime import decimal import re import struct from .base import BINARY from .base import DATETIMEOFFSET from .base import MSDialect from .base import MSExecutionContext from .base import VARBINARY from ... import exc from ... import types as sqltypes from ... import util from ...connectors.pyodbc import PyODBCConnector class _ms_numeric_pyodbc(object): """Turns Decimals with adjusted() < 0 or > 7 into strings. The routines here are needed for older pyodbc versions as well as current mxODBC versions. """ def bind_processor(self, dialect): super_process = super(_ms_numeric_pyodbc, self).bind_processor(dialect) if not dialect._need_decimal_fix: return super_process def process(value): if self.asdecimal and isinstance(value, decimal.Decimal): adjusted = value.adjusted() if adjusted < 0: return self._small_dec_to_string(value) elif adjusted > 7: return self._large_dec_to_string(value) if super_process: return super_process(value) else: return value return process # these routines needed for older versions of pyodbc. # as of 2.1.8 this logic is integrated. def _small_dec_to_string(self, value): return "%s0.%s%s" % ( (value < 0 and "-" or ""), "0" * (abs(value.adjusted()) - 1), "".join([str(nint) for nint in value.as_tuple()[1]]), ) def _large_dec_to_string(self, value): _int = value.as_tuple()[1] if "E" in str(value): result = "%s%s%s" % ( (value < 0 and "-" or ""), "".join([str(s) for s in _int]), "0" * (value.adjusted() - (len(_int) - 1)), ) else: if (len(_int) - 1) > value.adjusted(): result = "%s%s.%s" % ( (value < 0 and "-" or ""), "".join([str(s) for s in _int][0 : value.adjusted() + 1]), "".join([str(s) for s in _int][value.adjusted() + 1 :]), ) else: result = "%s%s" % ( (value < 0 and "-" or ""), "".join([str(s) for s in _int][0 : value.adjusted() + 1]), ) return result class _MSNumeric_pyodbc(_ms_numeric_pyodbc, sqltypes.Numeric): pass class _MSFloat_pyodbc(_ms_numeric_pyodbc, sqltypes.Float): pass class _ms_binary_pyodbc(object): """Wraps binary values in dialect-specific Binary wrapper. If the value is null, return a pyodbc-specific BinaryNull object to prevent pyODBC [and FreeTDS] from defaulting binary NULL types to SQLWCHAR and causing implicit conversion errors. """ def bind_processor(self, dialect): if dialect.dbapi is None: return None DBAPIBinary = dialect.dbapi.Binary def process(value): if value is not None: return DBAPIBinary(value) else: # pyodbc-specific return dialect.dbapi.BinaryNull return process class _ODBCDateTimeOffset(DATETIMEOFFSET): def bind_processor(self, dialect): def process(value): if value is None: return None elif isinstance(value, util.string_types): # if a string was passed directly, allow it through return value else: # Convert to string format required by T-SQL dto_string = value.strftime("%Y-%m-%d %H:%M:%S.%f %z") # offset needs a colon, e.g., -0700 -> -07:00 # "UTC offset in the form (+-)HHMM[SS[.ffffff]]" # backend currently rejects seconds / fractional seconds dto_string = re.sub( r"([\+\-]\d{2})([\d\.]+)$", r"\1:\2", dto_string ) return dto_string return process class _VARBINARY_pyodbc(_ms_binary_pyodbc, VARBINARY): pass class _BINARY_pyodbc(_ms_binary_pyodbc, BINARY): pass class MSExecutionContext_pyodbc(MSExecutionContext): _embedded_scope_identity = False def pre_exec(self): """where appropriate, issue "select scope_identity()" in the same statement. Background on why "scope_identity()" is preferable to "@@identity": http://msdn.microsoft.com/en-us/library/ms190315.aspx Background on why we attempt to embed "scope_identity()" into the same statement as the INSERT: http://code.google.com/p/pyodbc/wiki/FAQs#How_do_I_retrieve_autogenerated/identity_values? """ super(MSExecutionContext_pyodbc, self).pre_exec() # don't embed the scope_identity select into an # "INSERT .. DEFAULT VALUES" if ( self._select_lastrowid and self.dialect.use_scope_identity and len(self.parameters[0]) ): self._embedded_scope_identity = True self.statement += "; select scope_identity()" def post_exec(self): if self._embedded_scope_identity: # Fetch the last inserted id from the manipulated statement # We may have to skip over a number of result sets with # no data (due to triggers, etc.) while True: try: # fetchall() ensures the cursor is consumed # without closing it (FreeTDS particularly) row = self.cursor.fetchall()[0] break except self.dialect.dbapi.Error: # no way around this - nextset() consumes the previous set # so we need to just keep flipping self.cursor.nextset() self._lastrowid = int(row[0]) else: super(MSExecutionContext_pyodbc, self).post_exec() class MSDialect_pyodbc(PyODBCConnector, MSDialect): # mssql still has problems with this on Linux supports_sane_rowcount_returning = False execution_ctx_cls = MSExecutionContext_pyodbc colspecs = util.update_copy( MSDialect.colspecs, { sqltypes.Numeric: _MSNumeric_pyodbc, sqltypes.Float: _MSFloat_pyodbc, BINARY: _BINARY_pyodbc, DATETIMEOFFSET: _ODBCDateTimeOffset, # SQL Server dialect has a VARBINARY that is just to support # "deprecate_large_types" w/ VARBINARY(max), but also we must # handle the usual SQL standard VARBINARY VARBINARY: _VARBINARY_pyodbc, sqltypes.VARBINARY: _VARBINARY_pyodbc, sqltypes.LargeBinary: _VARBINARY_pyodbc, }, ) def __init__( self, description_encoding=None, fast_executemany=False, params ): if "description_encoding" in params: self.description_encoding = params.pop("description_encoding") super(MSDialect_pyodbc, self).__init__(params) self.use_scope_identity = ( self.use_scope_identity and self.dbapi and hasattr(self.dbapi.Cursor, "nextset") ) self._need_decimal_fix = self.dbapi and self._dbapi_version() < ( 2, 1, 8, ) self.fast_executemany = fast_executemany def _get_server_version_info(self, connection): try: # "Version of the instance of SQL Server, in the form # of 'major.minor.build.revision'" raw = connection.scalar( "SELECT CAST(SERVERPROPERTY('ProductVersion') AS VARCHAR)" ) except exc.DBAPIError: # SQL Server docs indicate this function isn't present prior to # 2008. Before we had the VARCHAR cast above, pyodbc would also # fail on this query. return super(MSDialect_pyodbc, self)._get_server_version_info( connection, allow_chars=False ) else: version = [] r = re.compile(r"[.\-]") for n in r.split(raw): try: version.append(int(n)) except ValueError: pass return tuple(version) def on_connect(self): super_ = super(MSDialect_pyodbc, self).on_connect() def on_connect(conn): if super_ is not None: super_(conn) self._setup_timestampoffset_type(conn) return on_connect def _setup_timestampoffset_type(self, connection): # output converter function for datetimeoffset def _handle_datetimeoffset(dto_value): tup = struct.unpack("<6hI2h", dto_value) return datetime.datetime( tup[0], tup[1], tup[2], tup[3], tup[4], tup[5], tup[6] // 1000, util.timezone( datetime.timedelta(hours=tup[7], minutes=tup[8]) ), ) odbc_SQL_SS_TIMESTAMPOFFSET = -155 # as defined in SQLNCLI.h connection.add_output_converter( odbc_SQL_SS_TIMESTAMPOFFSET, _handle_datetimeoffset ) def do_executemany(self, cursor, statement, parameters, context=None): if self.fast_executemany: cursor.fast_executemany = True super(MSDialect_pyodbc, self).do_executemany( cursor, statement, parameters, context=context ) def is_disconnect(self, e, connection, cursor): if isinstance(e, self.dbapi.Error): code = e.args[0] if code in { "08S01", "01000", "01002", "08003", "08007", "08S02", "08001", "HYT00", "HY010", "10054", }: return True return super(MSDialect_pyodbc, self).is_disconnect( e, connection, cursor ) dialect = MSDialect_pyodbc	15.93 KB	2026-01-20 12:58
📄 zxjdbc.py # mssql/zxjdbc.py # Copyright (C) 2005-2021 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """ .. dialect:: mssql+zxjdbc :name: zxJDBC for Jython :dbapi: zxjdbc :connectstring: mssql+zxjdbc://user:pass@host:port/dbname[?key=value&key=value...] :driverurl: http://jtds.sourceforge.net/ .. note:: Jython is not supported by current versions of SQLAlchemy. The zxjdbc dialect should be considered as experimental. """ # noqa from .base import MSDialect from .base import MSExecutionContext from ... import engine from ...connectors.zxJDBC import ZxJDBCConnector class MSExecutionContext_zxjdbc(MSExecutionContext): _embedded_scope_identity = False def pre_exec(self): super(MSExecutionContext_zxjdbc, self).pre_exec() # scope_identity after the fact returns null in jTDS so we must # embed it if self._select_lastrowid and self.dialect.use_scope_identity: self._embedded_scope_identity = True self.statement += "; SELECT scope_identity()" def post_exec(self): if self._embedded_scope_identity: while True: try: row = self.cursor.fetchall()[0] break except self.dialect.dbapi.Error: self.cursor.nextset() self._lastrowid = int(row[0]) if ( self.isinsert or self.isupdate or self.isdelete ) and self.compiled.returning: self._result_proxy = engine.FullyBufferedResultProxy(self) if self._enable_identity_insert: table = self.dialect.identifier_preparer.format_table( self.compiled.statement.table ) self.cursor.execute("SET IDENTITY_INSERT %s OFF" % table) class MSDialect_zxjdbc(ZxJDBCConnector, MSDialect): jdbc_db_name = "jtds:sqlserver" jdbc_driver_name = "net.sourceforge.jtds.jdbc.Driver" execution_ctx_cls = MSExecutionContext_zxjdbc def _get_server_version_info(self, connection): return tuple( int(x) for x in connection.connection.dbversion.split(".") ) dialect = MSDialect_zxjdbc	2.26 KB	2026-01-20 12:58

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