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