Hi, Thankyou very much for the suggestions.
Best Regards, A.Sreedhar. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 19, 2007 12:41 AM To: [email protected] Subject: Re: [sqlite]:Using sqlite3_progress_handler for GUI application Zbigniew Baniewski <[EMAIL PROTECTED]> wrote: > On Tue, Dec 18, 2007 at 12:24:25PM +0000, Simon Davies wrote: > > > Prob shd be http://www.sqlite.org/cvstrac/wiki?p=ScrollingCursor > > One question - using the example mentioned there: > > If we've created an index: CREATE INDEX example1 ON tracks(singer, > title); > > So, it'll make the query, like below, much faster: > > SELECT title FROM tracks > WHERE singer='Madonna' > AND title<:firsttitle > ORDER BY title DESC > LIMIT 5; > > ....but I understand, that when I'll try to add in the query a field > not covered by index "example1", like this: > > SELECT title FROM tracks > WHERE singer='Madonna' > AND title<:firsttitle > AND year_ed > 1985; > > ....so, then I'm losing every profit from having "example1" index, > right? Or perhaps "not quite every", and some speedup still remains - > just because _some_ columns are covered by example1 anyway? The index is still used to speed the search. But the extra "AND year_ed>1985" term requires SQLite to check each row coming out of the index an discard those for which the condition is not true. This might be a small or a large loss in performance, depending on how many rows match the condition. -- D. Richard Hipp <[EMAIL PROTECTED]> ---------------------------------------------------------------------------- - To unsubscribe, send email to [EMAIL PROTECTED] ---------------------------------------------------------------------------- - ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
