Projects/dibbler
Projects
/
dibbler
9
2
Fork 0
Code Issues 8 Pull Requests 1 Activity
dibbler/sqlalchemy/dialects/mssql/base.py

1298 lines
46 KiB
Python
Raw Normal View History

morro
2010-05-07 19:33:49 +02:00
# 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()