On Wed, Dec 7, 2016 at 3:11 PM, Simon Slavin <slav...@bigfraud.org> wrote:

>
> On 7 Dec 2016, at 8:40pm, David Raymond <david.raym...@tomtom.com> wrote:
>
> > Question on making indexes for the child fields of foreign keys. I have
> a child table with a number of foreign keys on fields which the majority of
> the time are null. I've currently got indexes on the child fields for the
> purposes of speeding up the foreign key checks, but what I'm wondering is
> if I used a conditional index which has "where fkField is not null", will
> that index be usable by the internal foreign key checker?
>
> Sorry, but the answer is no.  SQLite needs to be able to find the rows
> where the key-value is NULL.  It can’t do that from an index which doesn’t
> include those rows.
>
>
Why must SQLite find rows where the value is NULL? To me, this sounded like
a good enhancement request if it's not already the case. Am i missing
something?
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