Greg Obleshchuk wrote:
So in these cases there is no benefit from creating an index on a column
that is INTEGER PRIMARY KEY?
Putting an index on an INTEGER PRIMARY KEY will make INSERT,
DELETE, and UPDATE slower since the index must be maintained.
But no SELECT will ever use the index. So adding an index
to an INTEGER PRIMARY KEY is less than no benefit - it hurts.
See ticket #292. If you say "UNIQUE PRIMARY KEY" (as some
users want to do) SQLite will create two identical indices
Only one index will ever be used - the other justs wastes
CPU time and disk space. I'll get around to fixing that
someday. Probably at the same time I should rig it so that
attempts to create named indices on PRIMARY KEY are ignored
too. Once that happens, you can create indices on your
INTEGER PRIMARY KEY all you want - SQLite will ignore your
attempts - and everything will work at maximum efficiency
regardless of what you try to do.
--
D. Richard Hipp -- [EMAIL PROTECTED] -- 704.948.4565
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