diff options
Diffstat (limited to 'lib/sqlalchemy/dialects/mssql/base.py')
-rw-r--r-- | lib/sqlalchemy/dialects/mssql/base.py | 173 |
1 files changed, 131 insertions, 42 deletions
diff --git a/lib/sqlalchemy/dialects/mssql/base.py b/lib/sqlalchemy/dialects/mssql/base.py index dad02ee0f..92d7e4ab3 100644 --- a/lib/sqlalchemy/dialects/mssql/base.py +++ b/lib/sqlalchemy/dialects/mssql/base.py @@ -226,6 +226,53 @@ 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:`.Text` 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:`.Text` 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:`.Text` 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:`.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:`.NVARCHAR`, :class:`.VARCHAR`, :class:`.types.VARBINARY`, + :class:`.TEXT`, :class:`.mssql.NTEXT`, :class:`.mssql.IMAGE` will always remain + fixed and always output exactly that type. + +.. versionadded:: 1.0.0 + .. _mssql_indexes: Clustered Index Support @@ -367,19 +414,20 @@ import operator import re from ... import sql, schema as sa_schema, exc, util -from ...sql import compiler, expression, \ - util as sql_util, cast +from ...sql import compiler, expression, util as sql_util from ... import engine from ...engine import reflection, default from ... import types as sqltypes from ...types import INTEGER, BIGINT, SMALLINT, DECIMAL, NUMERIC, \ FLOAT, TIMESTAMP, DATETIME, DATE, BINARY,\ - VARBINARY, TEXT, VARCHAR, NVARCHAR, CHAR, NCHAR + TEXT, VARCHAR, NVARCHAR, CHAR, NCHAR from ...util import update_wrapper from . import information_schema as ischema +# http://sqlserverbuilds.blogspot.com/ +MS_2012_VERSION = (11,) MS_2008_VERSION = (10,) MS_2005_VERSION = (9,) MS_2000_VERSION = (8,) @@ -545,6 +593,26 @@ class NTEXT(sqltypes.UnicodeText): __visit_name__ = 'NTEXT' +class VARBINARY(sqltypes.VARBINARY, sqltypes.LargeBinary): + """The MSSQL VARBINARY type. + + This type extends both :class:`.types.VARBINARY` and + :class:`.types.LargeBinary`. In "deprecate_large_types" mode, + the :class:`.types.LargeBinary` type will produce ``VARBINARY(max)`` + on SQL Server. + + .. versionadded:: 1.0.0 + + .. seealso:: + + :ref:`mssql_large_type_deprecation` + + + + """ + __visit_name__ = 'VARBINARY' + + class IMAGE(sqltypes.LargeBinary): __visit_name__ = 'IMAGE' @@ -626,7 +694,6 @@ ischema_names = { class MSTypeCompiler(compiler.GenericTypeCompiler): - def _extend(self, spec, type_, length=None): """Extend a string-type declaration with standard SQL COLLATE annotations. @@ -647,103 +714,115 @@ class MSTypeCompiler(compiler.GenericTypeCompiler): return ' '.join([c for c in (spec, collation) if c is not None]) - def visit_FLOAT(self, type_): + 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_): + def visit_TINYINT(self, type_, **kw): return "TINYINT" - def visit_DATETIMEOFFSET(self, type_): + def visit_DATETIMEOFFSET(self, type_, **kw): if type_.precision: return "DATETIMEOFFSET(%s)" % type_.precision else: return "DATETIMEOFFSET" - def visit_TIME(self, type_): + def visit_TIME(self, type_, **kw): precision = getattr(type_, 'precision', None) if precision: return "TIME(%s)" % precision else: return "TIME" - def visit_DATETIME2(self, type_): + def visit_DATETIME2(self, type_, **kw): precision = getattr(type_, 'precision', None) if precision: return "DATETIME2(%s)" % precision else: return "DATETIME2" - def visit_SMALLDATETIME(self, type_): + def visit_SMALLDATETIME(self, type_, **kw): return "SMALLDATETIME" - def visit_unicode(self, type_): - return self.visit_NVARCHAR(type_) + 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_): - return self.visit_NTEXT(type_) + 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_): + def visit_NTEXT(self, type_, **kw): return self._extend("NTEXT", type_) - def visit_TEXT(self, type_): + def visit_TEXT(self, type_, **kw): return self._extend("TEXT", type_) - def visit_VARCHAR(self, type_): + def visit_VARCHAR(self, type_, **kw): return self._extend("VARCHAR", type_, length=type_.length or 'max') - def visit_CHAR(self, type_): + def visit_CHAR(self, type_, **kw): return self._extend("CHAR", type_) - def visit_NCHAR(self, type_): + def visit_NCHAR(self, type_, **kw): return self._extend("NCHAR", type_) - def visit_NVARCHAR(self, type_): + def visit_NVARCHAR(self, type_, **kw): return self._extend("NVARCHAR", type_, length=type_.length or 'max') - def visit_date(self, type_): + def visit_date(self, type_, **kw): if self.dialect.server_version_info < MS_2008_VERSION: - return self.visit_DATETIME(type_) + return self.visit_DATETIME(type_, **kw) else: - return self.visit_DATE(type_) + return self.visit_DATE(type_, **kw) - def visit_time(self, type_): + def visit_time(self, type_, **kw): if self.dialect.server_version_info < MS_2008_VERSION: - return self.visit_DATETIME(type_) + return self.visit_DATETIME(type_, **kw) else: - return self.visit_TIME(type_) + return self.visit_TIME(type_, **kw) - def visit_large_binary(self, type_): - return self.visit_IMAGE(type_) + 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_): + def visit_IMAGE(self, type_, **kw): return "IMAGE" - def visit_VARBINARY(self, type_): + def visit_VARBINARY(self, type_, **kw): return self._extend( "VARBINARY", type_, length=type_.length or 'max') - def visit_boolean(self, type_): + def visit_boolean(self, type_, **kw): return self.visit_BIT(type_) - def visit_BIT(self, type_): + def visit_BIT(self, type_, **kw): return "BIT" - def visit_MONEY(self, type_): + def visit_MONEY(self, type_, **kw): return "MONEY" - def visit_SMALLMONEY(self, type_): + def visit_SMALLMONEY(self, type_, **kw): return 'SMALLMONEY' - def visit_UNIQUEIDENTIFIER(self, type_): + def visit_UNIQUEIDENTIFIER(self, type_, **kw): return "UNIQUEIDENTIFIER" - def visit_SQL_VARIANT(self, type_): + def visit_SQL_VARIANT(self, type_, **kw): return 'SQL_VARIANT' @@ -1160,8 +1239,11 @@ class MSSQLStrictCompiler(MSSQLCompiler): class MSDDLCompiler(compiler.DDLCompiler): def get_column_specification(self, column, **kwargs): - colspec = (self.preparer.format_column(column) + " " - + self.dialect.type_compiler.process(column.type)) + colspec = ( + self.preparer.format_column(column) + " " + + 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 \ @@ -1370,13 +1452,15 @@ class MSDialect(default.DefaultDialect): query_timeout=None, use_scope_identity=True, max_identifier_length=None, - schema_name="dbo", **opts): + schema_name="dbo", + deprecate_large_types=None, **opts): self.query_timeout = int(query_timeout or 0) self.schema_name = schema_name self.use_scope_identity = use_scope_identity self.max_identifier_length = int(max_identifier_length or 0) or \ self.max_identifier_length + self.deprecate_large_types = deprecate_large_types super(MSDialect, self).__init__(**opts) def do_savepoint(self, connection, name): @@ -1390,6 +1474,9 @@ class MSDialect(default.DefaultDialect): def initialize(self, connection): super(MSDialect, self).initialize(connection) + self._setup_version_attributes() + + def _setup_version_attributes(self): if self.server_version_info[0] not in list(range(8, 17)): # FreeTDS with version 4.2 seems to report here # a number like "95.10.255". Don't know what @@ -1405,6 +1492,9 @@ class MSDialect(default.DefaultDialect): 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 _get_default_schema_name(self, connection): if self.server_version_info < MS_2005_VERSION: @@ -1592,12 +1682,11 @@ class MSDialect(default.DefaultDialect): if coltype in (MSString, MSChar, MSNVarchar, MSNChar, MSText, MSNText, MSBinary, MSVarBinary, sqltypes.LargeBinary): + if charlen == -1: + charlen = 'max' kwargs['length'] = charlen if collation: kwargs['collation'] = collation - if coltype == MSText or \ - (coltype in (MSString, MSNVarchar) and charlen == -1): - kwargs.pop('length') if coltype is None: util.warn( |