421 lines
15 KiB
Python
421 lines
15 KiB
Python
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# sybase/base.py
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# Copyright (C) 2010 Michael Bayer mike_mp@zzzcomputing.com
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# get_select_precolumns(), limit_clause() implementation
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# copyright (C) 2007 Fisch Asset Management
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# AG http://www.fam.ch, with coding by Alexander Houben
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# alexander.houben@thor-solutions.ch
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""Support for Sybase Adaptive Server Enterprise (ASE).
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Note that this dialect is no longer specific to Sybase iAnywhere.
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ASE is the primary support platform.
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"""
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import operator
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from sqlalchemy.sql import compiler, expression, text, bindparam
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from sqlalchemy.engine import default, base, reflection
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from sqlalchemy import types as sqltypes
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from sqlalchemy.sql import operators as sql_operators
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from sqlalchemy import schema as sa_schema
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from sqlalchemy import util, sql, exc
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from sqlalchemy.types import CHAR, VARCHAR, TIME, NCHAR, NVARCHAR,\
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TEXT,DATE,DATETIME, FLOAT, NUMERIC,\
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BIGINT,INT, INTEGER, SMALLINT, BINARY,\
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VARBINARY, DECIMAL, TIMESTAMP, Unicode,\
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UnicodeText
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RESERVED_WORDS = set([
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"add", "all", "alter", "and",
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"any", "as", "asc", "backup",
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"begin", "between", "bigint", "binary",
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"bit", "bottom", "break", "by",
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"call", "capability", "cascade", "case",
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"cast", "char", "char_convert", "character",
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"check", "checkpoint", "close", "comment",
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"commit", "connect", "constraint", "contains",
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"continue", "convert", "create", "cross",
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"cube", "current", "current_timestamp", "current_user",
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"cursor", "date", "dbspace", "deallocate",
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"dec", "decimal", "declare", "default",
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"delete", "deleting", "desc", "distinct",
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"do", "double", "drop", "dynamic",
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"else", "elseif", "encrypted", "end",
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"endif", "escape", "except", "exception",
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"exec", "execute", "existing", "exists",
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"externlogin", "fetch", "first", "float",
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"for", "force", "foreign", "forward",
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"from", "full", "goto", "grant",
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"group", "having", "holdlock", "identified",
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"if", "in", "index", "index_lparen",
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"inner", "inout", "insensitive", "insert",
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"inserting", "install", "instead", "int",
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"integer", "integrated", "intersect", "into",
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"iq", "is", "isolation", "join",
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"key", "lateral", "left", "like",
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"lock", "login", "long", "match",
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"membership", "message", "mode", "modify",
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"natural", "new", "no", "noholdlock",
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"not", "notify", "null", "numeric",
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"of", "off", "on", "open",
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"option", "options", "or", "order",
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"others", "out", "outer", "over",
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"passthrough", "precision", "prepare", "primary",
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"print", "privileges", "proc", "procedure",
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"publication", "raiserror", "readtext", "real",
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"reference", "references", "release", "remote",
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"remove", "rename", "reorganize", "resource",
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"restore", "restrict", "return", "revoke",
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"right", "rollback", "rollup", "save",
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"savepoint", "scroll", "select", "sensitive",
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"session", "set", "setuser", "share",
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"smallint", "some", "sqlcode", "sqlstate",
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"start", "stop", "subtrans", "subtransaction",
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"synchronize", "syntax_error", "table", "temporary",
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"then", "time", "timestamp", "tinyint",
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"to", "top", "tran", "trigger",
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"truncate", "tsequal", "unbounded", "union",
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"unique", "unknown", "unsigned", "update",
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"updating", "user", "using", "validate",
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"values", "varbinary", "varchar", "variable",
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"varying", "view", "wait", "waitfor",
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"when", "where", "while", "window",
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"with", "with_cube", "with_lparen", "with_rollup",
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"within", "work", "writetext",
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])
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class _SybaseUnitypeMixin(object):
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"""these types appear to return a buffer object."""
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def result_processor(self, dialect, coltype):
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def process(value):
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if value is not None:
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return str(value) #.decode("ucs-2")
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else:
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return None
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return process
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class UNICHAR(_SybaseUnitypeMixin, sqltypes.Unicode):
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__visit_name__ = 'UNICHAR'
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class UNIVARCHAR(_SybaseUnitypeMixin, sqltypes.Unicode):
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__visit_name__ = 'UNIVARCHAR'
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class UNITEXT(_SybaseUnitypeMixin, sqltypes.UnicodeText):
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__visit_name__ = 'UNITEXT'
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class TINYINT(sqltypes.Integer):
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__visit_name__ = 'TINYINT'
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class BIT(sqltypes.TypeEngine):
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__visit_name__ = 'BIT'
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class MONEY(sqltypes.TypeEngine):
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__visit_name__ = "MONEY"
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class SMALLMONEY(sqltypes.TypeEngine):
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__visit_name__ = "SMALLMONEY"
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class UNIQUEIDENTIFIER(sqltypes.TypeEngine):
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__visit_name__ = "UNIQUEIDENTIFIER"
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class IMAGE(sqltypes.LargeBinary):
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__visit_name__ = 'IMAGE'
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class SybaseTypeCompiler(compiler.GenericTypeCompiler):
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def visit_large_binary(self, type_):
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return self.visit_IMAGE(type_)
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def visit_boolean(self, type_):
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return self.visit_BIT(type_)
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def visit_unicode(self, type_):
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return self.visit_NVARCHAR(type_)
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def visit_UNICHAR(self, type_):
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return "UNICHAR(%d)" % type_.length
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def visit_UNIVARCHAR(self, type_):
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return "UNIVARCHAR(%d)" % type_.length
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def visit_UNITEXT(self, type_):
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return "UNITEXT"
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def visit_TINYINT(self, type_):
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return "TINYINT"
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def visit_IMAGE(self, type_):
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return "IMAGE"
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def visit_BIT(self, type_):
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return "BIT"
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def visit_MONEY(self, type_):
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return "MONEY"
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def visit_SMALLMONEY(self, type_):
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return "SMALLMONEY"
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def visit_UNIQUEIDENTIFIER(self, type_):
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return "UNIQUEIDENTIFIER"
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ischema_names = {
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'integer' : INTEGER,
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'unsigned int' : INTEGER, # TODO: unsigned flags
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'unsigned smallint' : SMALLINT, # TODO: unsigned flags
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'unsigned bigint' : BIGINT, # TODO: unsigned flags
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'bigint': BIGINT,
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'smallint' : SMALLINT,
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'tinyint' : TINYINT,
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'varchar' : VARCHAR,
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'long varchar' : TEXT, # TODO
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'char' : CHAR,
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'decimal' : DECIMAL,
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'numeric' : NUMERIC,
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'float' : FLOAT,
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'double' : NUMERIC, # TODO
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'binary' : BINARY,
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'varbinary' : VARBINARY,
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'bit': BIT,
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'image' : IMAGE,
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'timestamp': TIMESTAMP,
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'money': MONEY,
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'smallmoney': MONEY,
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'uniqueidentifier': UNIQUEIDENTIFIER,
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}
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class SybaseExecutionContext(default.DefaultExecutionContext):
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_enable_identity_insert = False
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def set_ddl_autocommit(self, connection, value):
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"""Must be implemented by subclasses to accommodate DDL executions.
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"connection" is the raw unwrapped DBAPI connection. "value"
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is True or False. when True, the connection should be configured
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such that a DDL can take place subsequently. when False,
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a DDL has taken place and the connection should be resumed
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into non-autocommit mode.
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"""
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raise NotImplementedError()
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def pre_exec(self):
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if self.isinsert:
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tbl = self.compiled.statement.table
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seq_column = tbl._autoincrement_column
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insert_has_sequence = seq_column is not None
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if insert_has_sequence:
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self._enable_identity_insert = seq_column.key in self.compiled_parameters[0]
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else:
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self._enable_identity_insert = False
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if self._enable_identity_insert:
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self.cursor.execute("SET IDENTITY_INSERT %s ON" %
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self.dialect.identifier_preparer.format_table(tbl))
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if self.isddl:
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# TODO: to enhance this, we can detect "ddl in tran" on the
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# database settings. this error message should be improved to
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# include a note about that.
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if not self.should_autocommit:
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raise exc.InvalidRequestError("The Sybase dialect only supports "
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"DDL in 'autocommit' mode at this time.")
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self.root_connection.engine.logger.info("AUTOCOMMIT (Assuming no Sybase 'ddl in tran')")
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self.set_ddl_autocommit(self.root_connection.connection.connection, True)
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def post_exec(self):
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if self.isddl:
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self.set_ddl_autocommit(self.root_connection, False)
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if self._enable_identity_insert:
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self.cursor.execute(
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"SET IDENTITY_INSERT %s OFF" %
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self.dialect.identifier_preparer.
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format_table(self.compiled.statement.table)
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)
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def get_lastrowid(self):
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cursor = self.create_cursor()
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cursor.execute("SELECT @@identity AS lastrowid")
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lastrowid = cursor.fetchone()[0]
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cursor.close()
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return lastrowid
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class SybaseSQLCompiler(compiler.SQLCompiler):
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ansi_bind_rules = True
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extract_map = util.update_copy(
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compiler.SQLCompiler.extract_map,
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{
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'doy': 'dayofyear',
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'dow': 'weekday',
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'milliseconds': 'millisecond'
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})
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def get_select_precolumns(self, select):
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s = select._distinct and "DISTINCT " or ""
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if select._limit:
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#if select._limit == 1:
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#s += "FIRST "
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#else:
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#s += "TOP %s " % (select._limit,)
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s += "TOP %s " % (select._limit,)
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if select._offset:
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if not select._limit:
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# FIXME: sybase doesn't allow an offset without a limit
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# so use a huge value for TOP here
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s += "TOP 1000000 "
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s += "START AT %s " % (select._offset+1,)
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return s
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def get_from_hint_text(self, table, text):
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return text
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def limit_clause(self, select):
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# Limit in sybase is after the select keyword
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return ""
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def visit_extract(self, extract, **kw):
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field = self.extract_map.get(extract.field, extract.field)
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return 'DATEPART("%s", %s)' % (field, self.process(extract.expr, **kw))
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def for_update_clause(self, select):
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# "FOR UPDATE" is only allowed on "DECLARE CURSOR" which SQLAlchemy doesn't use
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return ''
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def order_by_clause(self, select, **kw):
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kw['literal_binds'] = True
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order_by = self.process(select._order_by_clause, **kw)
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# SybaseSQL only allows ORDER BY in subqueries if there is a LIMIT
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if order_by and (not self.is_subquery() or select._limit):
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return " ORDER BY " + order_by
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else:
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return ""
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class SybaseDDLCompiler(compiler.DDLCompiler):
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def get_column_specification(self, column, **kwargs):
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colspec = self.preparer.format_column(column) + " " + \
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self.dialect.type_compiler.process(column.type)
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if column.table is None:
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raise exc.InvalidRequestError("The Sybase dialect requires Table-bound "\
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"columns in order to generate DDL")
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seq_col = column.table._autoincrement_column
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# install a IDENTITY Sequence if we have an implicit IDENTITY column
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if seq_col is column:
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sequence = isinstance(column.default, sa_schema.Sequence) and column.default
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if sequence:
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start, increment = sequence.start or 1, sequence.increment or 1
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else:
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start, increment = 1, 1
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if (start, increment) == (1, 1):
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colspec += " IDENTITY"
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else:
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# TODO: need correct syntax for this
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colspec += " IDENTITY(%s,%s)" % (start, increment)
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else:
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if column.nullable is not None:
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if not column.nullable or column.primary_key:
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colspec += " NOT NULL"
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else:
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colspec += " NULL"
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default = self.get_column_default_string(column)
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if default is not None:
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colspec += " DEFAULT " + default
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return colspec
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def visit_drop_index(self, drop):
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index = drop.element
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return "\nDROP INDEX %s.%s" % (
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self.preparer.quote_identifier(index.table.name),
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self.preparer.quote(self._validate_identifier(index.name, False), index.quote)
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)
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class SybaseIdentifierPreparer(compiler.IdentifierPreparer):
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reserved_words = RESERVED_WORDS
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class SybaseDialect(default.DefaultDialect):
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name = 'sybase'
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supports_unicode_statements = False
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supports_sane_rowcount = False
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supports_sane_multi_rowcount = False
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supports_native_boolean = False
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supports_unicode_binds = False
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postfetch_lastrowid = True
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colspecs = {}
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ischema_names = ischema_names
|
||
|
|
|
||
|
|
type_compiler = SybaseTypeCompiler
|
||
|
|
statement_compiler = SybaseSQLCompiler
|
||
|
|
ddl_compiler = SybaseDDLCompiler
|
||
|
|
preparer = SybaseIdentifierPreparer
|
||
|
|
|
||
|
|
def _get_default_schema_name(self, connection):
|
||
|
|
return connection.scalar(
|
||
|
|
text("SELECT user_name() as user_name", typemap={'user_name':Unicode})
|
||
|
|
)
|
||
|
|
|
||
|
|
def initialize(self, connection):
|
||
|
|
super(SybaseDialect, self).initialize(connection)
|
||
|
|
if self.server_version_info is not None and\
|
||
|
|
self.server_version_info < (15, ):
|
||
|
|
self.max_identifier_length = 30
|
||
|
|
else:
|
||
|
|
self.max_identifier_length = 255
|
||
|
|
|
||
|
|
@reflection.cache
|
||
|
|
def get_table_names(self, connection, schema=None, **kw):
|
||
|
|
if schema is None:
|
||
|
|
schema = self.default_schema_name
|
||
|
|
|
||
|
|
result = connection.execute(
|
||
|
|
text("select sysobjects.name from sysobjects, sysusers "
|
||
|
|
"where sysobjects.uid=sysusers.uid and "
|
||
|
|
"sysusers.name=:schemaname and "
|
||
|
|
"sysobjects.type='U'",
|
||
|
|
bindparams=[
|
||
|
|
bindparam('schemaname', schema)
|
||
|
|
])
|
||
|
|
)
|
||
|
|
return [r[0] for r in result]
|
||
|
|
|
||
|
|
def has_table(self, connection, tablename, schema=None):
|
||
|
|
if schema is None:
|
||
|
|
schema = self.default_schema_name
|
||
|
|
|
||
|
|
result = connection.execute(
|
||
|
|
text("select sysobjects.name from sysobjects, sysusers "
|
||
|
|
"where sysobjects.uid=sysusers.uid and "
|
||
|
|
"sysobjects.name=:tablename and "
|
||
|
|
"sysusers.name=:schemaname and "
|
||
|
|
"sysobjects.type='U'",
|
||
|
|
bindparams=[
|
||
|
|
bindparam('tablename', tablename),
|
||
|
|
bindparam('schemaname', schema)
|
||
|
|
])
|
||
|
|
)
|
||
|
|
return result.scalar() is not None
|
||
|
|
|
||
|
|
def reflecttable(self, connection, table, include_columns):
|
||
|
|
raise NotImplementedError()
|
||
|
|
|