"""
Support for Sybase via pyodbc.
http://pypi.python.org/pypi/pyodbc/
Connect strings are of the form::
sybase+pyodbc://<username>:<password>@<dsn>/
sybase+pyodbc://<username>:<password>@<host>/<database>
Unicode Support
---------------
The pyodbc driver currently supports usage of these Sybase types with
Unicode or multibyte strings::
CHAR
NCHAR
NVARCHAR
TEXT
VARCHAR
Currently *not* supported are::
UNICHAR
UNITEXT
UNIVARCHAR
"""
from sqlalchemy.dialects.sybase.base import SybaseDialect,SybaseExecutionContext
from sqlalchemy.connectors.pyodbc import PyODBCConnector
import decimal
from sqlalchemy import types
class _SybNumeric_pyodbc(sqltypes.Numeric):
"""Turns Decimals with adjusted() < -6 into floats.
It's not yet known how to get decimals with many
significant digits or very large adjusted() into Sybase
via pyodbc.
"""
def bind_processor(self, dialect):
super_process = super(_SybNumeric_pyodbc, self).bind_processor(dialect)
def process(value):
if self.asdecimal and \
isinstance(value, decimal.Decimal):
if value.adjusted() < -6:
return processors.to_float(value)
if super_process:
return super_process(value)
else:
return value
return process
class SybaseExecutionContext_pyodbc(SybaseExecutionContext):
def set_ddl_autocommit(self, connection, value):
if value:
connection.autocommit = True
else:
connection.autocommit = False
class SybaseDialect_pyodbc(PyODBCConnector, SybaseDialect):
execution_ctx_cls = SybaseExecutionContext_pyodbc
colspecs = {
sqltypes.Numeric:_SybNumeric_pyodbc,
}
dialect = SybaseDialect_pyodbc
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