insert_id not working

[eluser]Aken[/eluser]
Always use insert_id() directly after your query. Adding code in between could mess with the results.

Make sure the database table you're inserting into actually has a primary key. If it doesn't, insert_id() won't work.

Active Record is used by at least couple libraries (Session being the main one). It is not required to use in your application, but it is used by other CI components, yes.