Unexpected behavior with regexp model filtering (Sqlite)

Bensiins-MacBook-Pro:myproject benicorp$ python manage.py shell
Python 2.7.3 (v2.7.3:70274d53c1dd, Apr 9 2012, 20:52:43)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> import sqlite3, re
>>> from settings import DATABASES
>>> def regexp(pattern, item):
... reg = re.compile(pattern)
... return reg.match(item) is not None
...
>>> loc = DATABASES['default']['NAME']
>>> conn = sqlite3.connect(loc)
>>> conn.create_function("REGEXP", 2, regexp)
>>> c=conn.cursor()
>>> c.execute("select * from myapp_word where arpabet REGEXP '; M.*'")
<sqlite3.Cursor object at 0x101cb55e0>
>>> res=c.fetchall()
>>> len(res)
8639
>>> test=[r for r in res if r[2][2]!="M"]
>>> len(test)
0
>>> conn.close()
>>> from myapp.models import Word
>>> res2 = Word.objects.filter(arpabet__regex='; M.*')
>>> res2=list(res2)
>>> len(res2)
18333
>>> test2 =[r for r in res2 if r.arpabet[2]!="M"]
>>> len(test2)
9694
>>> 18333-8639
9694

Hi,

I'm getting stuck on figuring out why regex searches are matching any part of a field when I use my model's regexp filter (instead of matching linearly); they're behaving like calls to re.search instead of re.match.

Since I'm using Sqlite, I registered my own function based on Python's re.match. I tried testing the function in a shell by directly connecting to the database to search the field and comparing those results to using the model's regexp filter. The filter returns significantly more items and when I test to see if they are strict matches for the regexp the 'extra' ones fail. 

I'm attaching a transcript of the shell tests.

Any insight or advice would be greatly appreciated.

Beni

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