# mssql.py """Support for the Microsoft SQL Server database. Connecting ---------- See the individual driver sections below for details on connecting. Auto Increment Behavior ----------------------- ``IDENTITY`` columns are supported by using SQLAlchemy ``schema.Sequence()`` objects. In other words:: Table('test', mss_engine, Column('id', Integer, Sequence('blah',100,10), primary_key=True), Column('name', String(20)) ).create() would yield:: CREATE TABLE test ( id INTEGER NOT NULL IDENTITY(100,10) PRIMARY KEY, name VARCHAR(20) NULL, ) Note that the ``start`` and ``increment`` values for sequences are optional and will default to 1,1. Implicit ``autoincrement`` behavior works the same in MSSQL as it does in other dialects and results in an ``IDENTITY`` column. * Support for ``SET IDENTITY_INSERT ON`` mode (automagic on / off for ``INSERT`` s) * Support for auto-fetching of ``@@IDENTITY/@@SCOPE_IDENTITY()`` on ``INSERT`` Collation Support ----------------- MSSQL specific string types support a collation parameter that creates a column-level specific collation for the column. The collation parameter accepts a Windows Collation Name or a SQL Collation Name. Supported types are MSChar, MSNChar, MSString, MSNVarchar, MSText, and MSNText. For example:: Column('login', String(32, collation='Latin1_General_CI_AS')) will yield:: login VARCHAR(32) COLLATE Latin1_General_CI_AS NULL LIMIT/OFFSET Support -------------------- MSSQL has no support for the LIMIT or OFFSET keysowrds. 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. 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. Compatibility Levels -------------------- MSSQL supports the notion of setting compatibility levels at the database level. This allows, for instance, to run a database that is compatibile with SQL2000 while running on a SQL2005 database server. ``server_version_info`` will always retrun the database server version information (in this case SQL2005) and not the compatibiility level information. Because of this, if running under a backwards compatibility mode SQAlchemy may attempt to use T-SQL statements that are unable to be parsed by the database server. Known Issues ------------ * No support for more than one ``IDENTITY`` column per table """ import datetime, decimal, inspect, operator, sys, re import itertools from sqlalchemy import sql, schema as sa_schema, exc, util from sqlalchemy.sql import select, compiler, expression, \ operators as sql_operators, \ functions as sql_functions, util as sql_util from sqlalchemy.engine import default, base, reflection from sqlalchemy import types as sqltypes from sqlalchemy import processors from sqlalchemy.types import INTEGER, BIGINT, SMALLINT, DECIMAL, NUMERIC, \ FLOAT, TIMESTAMP, DATETIME, DATE, BINARY,\ VARBINARY, BLOB from sqlalchemy.dialects.mssql import information_schema as ischema 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.Float): """A type for ``real`` numbers.""" __visit_name__ = 'REAL' def __init__(self): super(REAL, self).__init__(precision=24) 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, basestring): return datetime.date(*[int(x or 0) for x in self._reg.match(value).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): value = datetime.datetime.combine(self.__zero_date, value) return value return process _reg = re.compile(r"(\d+):(\d+):(\d+)(?:\.(\d+))?") def result_processor(self, dialect, coltype): def process(value): if isinstance(value, datetime.datetime): return value.time() elif isinstance(value, basestring): return datetime.time(*[int(x or 0) for x in self._reg.match(value).groups()]) else: return value return process class _DateTimeBase(object): def bind_processor(self, dialect): def process(value): # TODO: why ? 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, **kwargs): 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 _StringType(object): """Base for MSSQL string types.""" def __init__(self, collation=None): self.collation = collation class TEXT(_StringType, sqltypes.TEXT): """MSSQL TEXT type, for variable-length text up to 2^31 characters.""" def __init__(self, *args, **kw): """Construct a TEXT. :param collation: Optional, a column-level collation for this string value. Accepts a Windows Collation Name or a SQL Collation Name. """ collation = kw.pop('collation', None) _StringType.__init__(self, collation) sqltypes.Text.__init__(self, *args, **kw) class NTEXT(_StringType, sqltypes.UnicodeText): """MSSQL NTEXT type, for variable-length unicode text up to 2^30 characters.""" __visit_name__ = 'NTEXT' def __init__(self, *args, **kwargs): """Construct a NTEXT. :param collation: Optional, a column-level collation for this string value. Accepts a Windows Collation Name or a SQL Collation Name. """ collation = kwargs.pop('collation', None) _StringType.__init__(self, collation) length = kwargs.pop('length', None) sqltypes.UnicodeText.__init__(self, length, **kwargs) class VARCHAR(_StringType, sqltypes.VARCHAR): """MSSQL VARCHAR type, for variable-length non-Unicode data with a maximum of 8,000 characters.""" def __init__(self, *args, **kw): """Construct a VARCHAR. :param length: Optinal, maximum data length, in characters. :param convert_unicode: defaults to False. If True, convert ``unicode`` data sent to the database to a ``str`` bytestring, and convert bytestrings coming back from the database into ``unicode``. Bytestrings are encoded using the dialect's :attr:`~sqlalchemy.engine.base.Dialect.encoding`, which defaults to `utf-8`. If False, may be overridden by :attr:`sqlalchemy.engine.base.Dialect.convert_unicode`. :param collation: Optional, a column-level collation for this string value. Accepts a Windows Collation Name or a SQL Collation Name. """ collation = kw.pop('collation', None) _StringType.__init__(self, collation) sqltypes.VARCHAR.__init__(self, *args, **kw) class NVARCHAR(_StringType, sqltypes.NVARCHAR): """MSSQL NVARCHAR type. For variable-length unicode character data up to 4,000 characters.""" def __init__(self, *args, **kw): """Construct a NVARCHAR. :param length: Optional, Maximum data length, in characters. :param collation: Optional, a column-level collation for this string value. Accepts a Windows Collation Name or a SQL Collation Name. """ collation = kw.pop('collation', None) _StringType.__init__(self, collation) sqltypes.NVARCHAR.__init__(self, *args, **kw) class CHAR(_StringType, sqltypes.CHAR): """MSSQL CHAR type, for fixed-length non-Unicode data with a maximum of 8,000 characters.""" def __init__(self, *args, **kw): """Construct a CHAR. :param length: Optinal, maximum data length, in characters. :param convert_unicode: defaults to False. If True, convert ``unicode`` data sent to the database to a ``str`` bytestring, and convert bytestrings coming back from the database into ``unicode``. Bytestrings are encoded using the dialect's :attr:`~sqlalchemy.engine.base.Dialect.encoding`, which defaults to `utf-8`. If False, may be overridden by :attr:`sqlalchemy.engine.base.Dialect.convert_unicode`. :param collation: Optional, a column-level collation for this string value. Accepts a Windows Collation Name or a SQL Collation Name. """ collation = kw.pop('collation', None) _StringType.__init__(self, collation) sqltypes.CHAR.__init__(self, *args, **kw) class NCHAR(_StringType, sqltypes.NCHAR): """MSSQL NCHAR type. For fixed-length unicode character data up to 4,000 characters.""" def __init__(self, *args, **kw): """Construct an NCHAR. :param length: Optional, Maximum data length, in characters. :param collation: Optional, a column-level collation for this string value. Accepts a Windows Collation Name or a SQL Collation Name. """ collation = kw.pop('collation', None) _StringType.__init__(self, collation) sqltypes.NCHAR.__init__(self, *args, **kw) class IMAGE(sqltypes.LargeBinary): __visit_name__ = 'IMAGE' 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' # 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, 'timestamp': TIMESTAMP, 'money': MONEY, 'smallmoney': SMALLMONEY, 'uniqueidentifier': UNIQUEIDENTIFIER, 'sql_variant': SQL_VARIANT, } class MSTypeCompiler(compiler.GenericTypeCompiler): def _extend(self, spec, type_): """Extend a string-type declaration with standard SQL COLLATE annotations. """ if getattr(type_, 'collation', None): collation = 'COLLATE %s' % type_.collation else: collation = None if type_.length: spec = spec + "(%d)" % type_.length return ' '.join([c for c in (spec, collation) if c is not None]) def visit_FLOAT(self, type_): precision = getattr(type_, 'precision', None) if precision is None: return "FLOAT" else: return "FLOAT(%(precision)s)" % {'precision': precision} def visit_REAL(self, type_): return "REAL" def visit_TINYINT(self, type_): return "TINYINT" def visit_DATETIMEOFFSET(self, type_): if type_.precision: return "DATETIMEOFFSET(%s)" % type_.precision else: return "DATETIMEOFFSET" def visit_TIME(self, type_): precision = getattr(type_, 'precision', None) if precision: return "TIME(%s)" % precision else: return "TIME" def visit_DATETIME2(self, type_): precision = getattr(type_, 'precision', None) if precision: return "DATETIME2(%s)" % precision else: return "DATETIME2" def visit_SMALLDATETIME(self, type_): return "SMALLDATETIME" def visit_unicode(self, type_): return self.visit_NVARCHAR(type_) def visit_unicode_text(self, type_): return self.visit_NTEXT(type_) def visit_NTEXT(self, type_): return self._extend("NTEXT", type_) def visit_TEXT(self, type_): return self._extend("TEXT", type_) def visit_VARCHAR(self, type_): return self._extend("VARCHAR", type_) def visit_CHAR(self, type_): return self._extend("CHAR", type_) def visit_NCHAR(self, type_): return self._extend("NCHAR", type_) def visit_NVARCHAR(self, type_): return self._extend("NVARCHAR", type_) def visit_date(self, type_): if self.dialect.server_version_info < MS_2008_VERSION: return self.visit_DATETIME(type_) else: return self.visit_DATE(type_) def visit_time(self, type_): if self.dialect.server_version_info < MS_2008_VERSION: return self.visit_DATETIME(type_) else: return self.visit_TIME(type_) def visit_large_binary(self, type_): return self.visit_IMAGE(type_) def visit_IMAGE(self, type_): return "IMAGE" def visit_boolean(self, type_): return self.visit_BIT(type_) def visit_BIT(self, type_): return "BIT" def visit_MONEY(self, type_): return "MONEY" def visit_SMALLMONEY(self, type_): return 'SMALLMONEY' def visit_UNIQUEIDENTIFIER(self, type_): return "UNIQUEIDENTIFIER" def visit_SQL_VARIANT(self, type_): return 'SQL_VARIANT' class MSExecutionContext(default.DefaultExecutionContext): _enable_identity_insert = False _select_lastrowid = False _result_proxy = None _lastrowid = None 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] else: self._enable_identity_insert = False self._select_lastrowid = insert_has_sequence and \ not self.compiled.returning and \ not self._enable_identity_insert and \ not self.executemany if self._enable_identity_insert: self.cursor.execute("SET IDENTITY_INSERT %s ON" % self.dialect.identifier_preparer.format_table(tbl)) def post_exec(self): """Disable IDENTITY_INSERT if enabled.""" if self._select_lastrowid: if self.dialect.use_scope_identity: self.cursor.execute("SELECT scope_identity() AS lastrowid", ()) else: self.cursor.execute("SELECT @@identity AS lastrowid", ()) # 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 = base.FullyBufferedResultProxy(self) if self._enable_identity_insert: self.cursor.execute( "SET IDENTITY_INSERT %s OFF" % self.dialect.identifier_preparer. format_table(self.compiled.statement.table) ) def get_lastrowid(self): return self._lastrowid def handle_dbapi_exception(self, e): if self._enable_identity_insert: try: self.cursor.execute("SET IDENTITY_INSERT %s OFF" % self.dialect.\ identifier_preparer.\ format_table(self.compiled.statement.table) ) except: pass def get_result_proxy(self): if self._result_proxy: return self._result_proxy else: return base.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): super(MSSQLCompiler, self).__init__(*args, **kwargs) self.tablealiases = {} 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(self, binary, **kw): return "%s + %s" % (self.process(binary.left, **kw), self.process(binary.right, **kw)) def visit_match_op(self, binary, **kw): return "CONTAINS (%s, %s)" % ( self.process(binary.left, **kw), self.process(binary.right, **kw)) def get_select_precolumns(self, select): """ MS-SQL puts TOP, it's version of LIMIT here """ if select._distinct or select._limit: s = select._distinct and "DISTINCT " or "" if select._limit: if not select._offset: s += "TOP %s " % (select._limit,) return s return compiler.SQLCompiler.get_select_precolumns(self, select) def limit_clause(self, select): # Limit in mssql is after the select keyword return "" 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 getattr(select, '_mssql_visit', None) and select._offset: # to use ROW_NUMBER(), an ORDER BY is required. orderby = self.process(select._order_by_clause) if not orderby: raise exc.InvalidRequestError('MSSQL requires an order_by when ' 'using an offset.') _offset = select._offset _limit = select._limit select._mssql_visit = True select = select.column(sql.literal_column("ROW_NUMBER() OVER (ORDER BY %s)" % orderby).label("mssql_rn") ).order_by(None).alias() limitselect = sql.select([c for c in select.c if c.key!='mssql_rn']) limitselect.append_whereclause("mssql_rn>%d" % _offset) if _limit is not None: limitselect.append_whereclause("mssql_rn<=%d" % (_limit + _offset)) return self.process(limitselect, iswrapper=True, **kwargs) else: return compiler.SQLCompiler.visit_select(self, select, **kwargs) 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_table(self, table, mssql_aliased=False, **kwargs): if mssql_aliased: 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=True, **kwargs) else: return super(MSSQLCompiler, self).visit_table(table, **kwargs) def visit_alias(self, alias, **kwargs): # translate for schema-qualified table aliases self.tablealiases[alias.original] = alias kwargs['mssql_aliased'] = True return super(MSSQLCompiler, self).visit_alias(alias, **kwargs) 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_rollback_to_savepoint(self, savepoint_stmt): return ("ROLLBACK TRANSACTION %s" % self.preparer.format_savepoint(savepoint_stmt)) def visit_column(self, column, result_map=None, **kwargs): 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 result_map is not None: result_map[column.name.lower()] = (column.name, (column, ), column.type) return super(MSSQLCompiler, self).visit_column(converted, result_map=None, **kwargs) return super(MSSQLCompiler, self).visit_column(column, result_map=result_map, **kwargs) def visit_binary(self, binary, **kwargs): """Move bind parameters to the right-hand side of an operator, where possible. """ if ( isinstance(binary.left, expression._BindParamClause) and binary.operator == operator.eq and not isinstance(binary.right, expression._BindParamClause) ): return self.process(expression._BinaryExpression(binary.right, binary.left, binary.operator), **kwargs) else: if ( (binary.operator is operator.eq or binary.operator is operator.ne) and ( (isinstance(binary.left, expression._FromGrouping) and isinstance(binary.left.element, expression._ScalarSelect)) or (isinstance(binary.right, expression._FromGrouping) and isinstance(binary.right.element, expression._ScalarSelect)) or isinstance(binary.left, expression._ScalarSelect) or isinstance(binary.right, expression._ScalarSelect) ) ): op = binary.operator == operator.eq and "IN" or "NOT IN" return self.process(expression._BinaryExpression(binary.left, binary.right, op), **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) def col_label(col): adapted = adapter.traverse(col) if isinstance(col, expression._Label): return adapted.label(c.key) else: return self.label_select_column(None, adapted, asfrom=False) columns = [ self.process( col_label(c), within_columns_clause=True, result_map=self.result_map ) for c in expression._select_iterables(returning_cols) ] return 'OUTPUT ' + ', '.join(columns) 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): order_by = self.process(select._order_by_clause, **kw) # MSSQL only allows ORDER BY in subqueries if there is a LIMIT if order_by and (not self.is_subquery() or select._limit): return " ORDER BY " + order_by else: return "" 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(self, binary, **kw): kw['literal_binds'] = True return "%s IN %s" % ( self.process(binary.left, **kw), self.process(binary.right, **kw) ) def visit_notin_op(self, binary, **kw): kw['literal_binds'] = True return "%s NOT IN %s" % ( self.process(binary.left, **kw), self.process(binary.right, **kw) ) def visit_function(self, func, **kw): kw['literal_binds'] = True return super(MSSQLStrictCompiler, self).visit_function(func, **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) + " " + self.dialect.type_compiler.process(column.type)) if column.nullable is not None: if not column.nullable or column.primary_key: colspec += " NOT NULL" else: colspec += " NULL" if column.table is None: raise exc.InvalidRequestError("mssql requires Table-bound columns " "in order to generate DDL") seq_col = column.table._autoincrement_column # install a IDENTITY Sequence if we have an implicit IDENTITY column if seq_col is column: sequence = isinstance(column.default, sa_schema.Sequence) and column.default if sequence: start, increment = sequence.start or 1, sequence.increment or 1 else: start, increment = 1, 1 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_drop_index(self, drop): return "\nDROP INDEX %s.%s" % ( self.preparer.quote_identifier(drop.element.table.name), self.preparer.quote(self._validate_identifier(drop.element.name, False), drop.element.quote) ) class MSIdentifierPreparer(compiler.IdentifierPreparer): reserved_words = RESERVED_WORDS def __init__(self, dialect): super(MSIdentifierPreparer, self).__init__(dialect, initial_quote='[', final_quote=']') def _escape_identifier(self, value): return value def quote_schema(self, schema, force=True): """Prepare a quoted table and schema name.""" result = '.'.join([self.quote(x, force) for x in schema.split('.')]) return result 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, } ischema_names = ischema_names supports_native_boolean = False supports_unicode_binds = True postfetch_lastrowid = True server_version_info = () statement_compiler = MSSQLCompiler ddl_compiler = MSDDLCompiler type_compiler = MSTypeCompiler preparer = MSIdentifierPreparer def __init__(self, query_timeout=None, use_scope_identity=True, max_identifier_length=None, schema_name=u"dbo", **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 super(MSDialect, self).__init__(**opts) def do_savepoint(self, connection, name): util.warn("Savepoint support in mssql is experimental and " "may lead to data loss.") connection.execute("IF @@TRANCOUNT = 0 BEGIN TRANSACTION") connection.execute("SAVE TRANSACTION %s" % name) def do_release_savepoint(self, connection, name): pass def initialize(self, connection): super(MSDialect, self).initialize(connection) if self.server_version_info >= MS_2005_VERSION and \ 'implicit_returning' not in self.__dict__: self.implicit_returning = True def _get_default_schema_name(self, connection): user_name = connection.scalar("SELECT user_name() as user_name;") if user_name is not None: # now, get the default schema query = """ SELECT default_schema_name FROM sys.database_principals WHERE name = ? AND type = 'S' """ try: default_schema_name = connection.scalar(query, [user_name]) if default_schema_name is not None: return unicode(default_schema_name) except: pass return self.schema_name def has_table(self, connection, tablename, schema=None): current_schema = schema or self.default_schema_name columns = ischema.columns if current_schema: whereclause = sql.and_(columns.c.table_name==tablename, columns.c.table_schema==current_schema) else: whereclause = columns.c.table_name==tablename 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 def get_table_names(self, connection, schema=None, **kw): current_schema = schema or self.default_schema_name tables = ischema.tables s = sql.select([tables.c.table_name], sql.and_( tables.c.table_schema == current_schema, tables.c.table_type == u'BASE TABLE' ), order_by=[tables.c.table_name] ) table_names = [r[0] for r in connection.execute(s)] return table_names @reflection.cache def get_view_names(self, connection, schema=None, **kw): current_schema = schema or self.default_schema_name tables = ischema.tables s = sql.select([tables.c.table_name], sql.and_( tables.c.table_schema == current_schema, tables.c.table_type == u'VIEW' ), order_by=[tables.c.table_name] ) view_names = [r[0] for r in connection.execute(s)] return view_names # The cursor reports it is closed after executing the sp. @reflection.cache def get_indexes(self, connection, tablename, schema=None, **kw): current_schema = schema or self.default_schema_name col_finder = re.compile("(\w+)") full_tname = "%s.%s" % (current_schema, tablename) indexes = [] s = sql.text("exec sp_helpindex '%s'" % full_tname) rp = connection.execute(s) if rp.closed: # did not work for this setup. return [] for row in rp: if 'primary key' not in row['index_description']: indexes.append({ 'name' : row['index_name'], 'column_names' : col_finder.findall(row['index_keys']), 'unique': 'unique' in row['index_description'] }) return indexes @reflection.cache def get_view_definition(self, connection, viewname, schema=None, **kw): current_schema = schema or self.default_schema_name views = ischema.views s = sql.select([views.c.view_definition], sql.and_( views.c.table_schema == current_schema, views.c.table_name == viewname ), ) rp = connection.execute(s) if rp: view_def = rp.scalar() return view_def @reflection.cache def get_columns(self, connection, tablename, schema=None, **kw): # Get base columns current_schema = schema or self.default_schema_name columns = ischema.columns if current_schema: whereclause = sql.and_(columns.c.table_name==tablename, columns.c.table_schema==current_schema) else: whereclause = columns.c.table_name==tablename s = sql.select([columns], whereclause, order_by=[columns.c.ordinal_position]) c = connection.execute(s) cols = [] while True: row = c.fetchone() if row is None: break (name, type, nullable, charlen, numericprec, numericscale, default, collation) = ( row[columns.c.column_name], row[columns.c.data_type], row[columns.c.is_nullable] == 'YES', row[columns.c.character_maximum_length], row[columns.c.numeric_precision], row[columns.c.numeric_scale], row[columns.c.column_default], row[columns.c.collation_name] ) coltype = self.ischema_names.get(type, None) kwargs = {} if coltype in (MSString, MSChar, MSNVarchar, MSNChar, MSText, MSNText, MSBinary, MSVarBinary, sqltypes.LargeBinary): 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("Did not recognize type '%s' of column '%s'" % (type, name)) coltype = sqltypes.NULLTYPE if issubclass(coltype, sqltypes.Numeric) and coltype is not MSReal: kwargs['scale'] = numericscale kwargs['precision'] = numericprec coltype = coltype(**kwargs) cdict = { 'name' : name, 'type' : coltype, 'nullable' : nullable, 'default' : default, 'autoincrement':False, } 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("sp_columns @table_name = '%s', " "@table_owner = '%s'" % (tablename, current_schema)) 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]['sequence'] = dict( name='%s_identity' % col_name) break cursor.close() if ic is not None and self.server_version_info >= MS_2005_VERSION: table_fullname = "%s.%s" % (current_schema, 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]['sequence'].update({ 'start' : int(row[0]), 'increment' : int(row[1]) }) return cols @reflection.cache def get_primary_keys(self, connection, tablename, schema=None, **kw): current_schema = schema or self.default_schema_name pkeys = [] RR = ischema.ref_constraints # information_schema.referential_constraints TC = ischema.constraints # information_schema.table_constraints C = ischema.key_constraints.alias('C') # information_schema.constraint_column_usage: # the constrained column R = ischema.key_constraints.alias('R') # information_schema.constraint_column_usage: # the referenced column # Primary key constraints s = sql.select([C.c.column_name, TC.c.constraint_type], sql.and_(TC.c.constraint_name == C.c.constraint_name, C.c.table_name == tablename, C.c.table_schema == current_schema) ) c = connection.execute(s) for row in c: if 'PRIMARY' in row[TC.c.constraint_type.name]: pkeys.append(row[0]) return pkeys @reflection.cache def get_foreign_keys(self, connection, tablename, schema=None, **kw): current_schema = schema or self.default_schema_name # Add constraints RR = ischema.ref_constraints #information_schema.referential_constraints TC = ischema.constraints #information_schema.table_constraints C = ischema.key_constraints.alias('C') # information_schema.constraint_column_usage: # the constrained column R = ischema.key_constraints.alias('R') # information_schema.constraint_column_usage: # the referenced column # 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 == current_schema, C.c.constraint_name == RR.c.constraint_name, R.c.constraint_name == RR.c.unique_constraint_name, 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 = [] fknm, scols, rcols = (None, [], []) 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 current_schema != rschema: rec['referred_schema'] = rschema local_cols, remote_cols = rec['constrained_columns'], rec['referred_columns'] local_cols.append(scol) remote_cols.append(rcol) return fkeys.values()