sqlite3 puzzle

Rob Day robert.day at merton.oxon.org
Tue Jan 15 15:36:51 CET 2013


On 15 January 2013 07:09, llanitedave <llanitedave at veawb.coop> wrote:

> So I put the following test code in my initialization method:
>
>     # open database file
>     self.geologger_db = sqlite3.connect('geologger.mgc')
>     self.db_cursor = self.geologger_db.cursor()
>     self.foreign_key_status = self.db_cursor.execute("PRAGMA foreign_keys = ON")
>     self.foreign_key_status = self.foreign_key_status.fetchone()
>
>     print self.foreign_key_status
>
> I ran this several times while I was arranging the downstream queries, and each time it returned '(1,)', which means foreign keys is enabled.
>
> But I was using a variable named 'cmd1' as a placeholder until I changed the name to
> the more descriptive 'self.foreign_key_status'.  Since I made the name change, however,
> the code only returns 'None'.  Reverting to the previous variable name has no effect.

Hmm - your code doesn't quite match up with the docs at
http://docs.python.org/2/library/sqlite3.html. That seems to suggest
that you should call fetchone() on the cursor, not on the result of
execute().

Does the following work?

    # open database file
    self.geologger_db = sqlite3.connect('geologger.mgc')
    self.db_cursor = self.geologger_db.cursor()
    self.db_cursor.execute("PRAGMA foreign_keys = ON")
    print self.db_cursor.fetchone()


--
Robert K. Day
robert.day at merton.oxon.org



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