# 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
from sqlalchemy.sql import operators
from sqlalchemy import 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()
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