[Patch] MS-SQL backend via pymssql

[Cheng <czhang.cmu+web@…>]

The patches are based on the work of Jakub Labath <jlabath_AT_gmail.com>. I merely helped to cut the doctest errors down to 2.

This wrapper requires ​pymssql. I tested with pymssql 0.7.3. A patch of pymssql is attached for boolean typecast and autocommit.
The patches tested with Django [2100]. 2 errors left:

'subclassing' module: API test failed
=====================================
Code: 'a3.pub_date'
Line: 66
Expected: 'datetime.date(2005, 8, 22)\n'
Got: 'datetime.datetime(2005, 8, 22, 0, 0)\n'

'subclassing' module: API test failed
=====================================
Code: 'a4.pub_date'
Line: 86
Expected: 'datetime.date(2005, 8, 22)\n'
Got: 'datetime.datetime(2005, 8, 22, 0, 0)\n'
2 errors:

The pymssql provides no hook to do custom typecasts. With the hints from ​this email thread, I still couldn't find a place to cast MSSQL's native datetime to date or time, if the field type is 'DateField' or 'TimeField'.

BTW: I just noticed that pymssql says it works on Windows as well. I didn't test it, but if so, it's more flexible than adodbapi then.

[Cheng <czhang.cmu+web@…>]

patch for pymssql

[Cheng <czhang.cmu+web@…>]

django/core/db/backend/mssql.py

[Cheng <czhang.cmu+web@…>]

patch for other files

[Adrian Holovaty]

Closed in favor of #1429.