I suspect that there are some problems with IMMEDIATE.
http://www.sqlite.org/lang_transaction.html

I am not a DB guy and I don't know the "best" answer, if there even is one.

I mean if process A reads the DB and then wants to update some record, but process B has read the same record and want's to update it too! Who's update "wins"? Maybe this is a complicated thing where if process A had known about process B's update in advance, it would have made a different decision? In other words, what process A will do is "nonsense" given what process B just did. If this is a single field in a record, maybe a password, I can see it..last guy wins and there is really not a problem. If each update is "atomic" and self consistent, then maybe this IMMEDIATE keyword is not necessary? I defer to the DB guru's here.