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Re^2: Does DBI handle table alias?

by The_Rabbit (Acolyte)
on Oct 06, 2004 at 19:18 UTC ( #397145=note: print w/replies, xml ) Need Help??


in reply to Re: Does DBI handle table alias?
in thread Does DBI handle table alias?

You should investigate what kind query analysis tools your DBMS has. There should be a tool that will tell you what type of execution path your DBMS is planning for your query. Generally, these will help you determine where indexes are useful.

If you have absolutely no indexes then for every query you are doing a full table scan instead of an index scan. So, adding a n index will improve performance dramatically. Most likely by at LEAST an order of magnitude and possibly even more than that.

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Re^3: Does DBI handle table alias?
by dws (Chancellor) on Oct 07, 2004 at 05:09 UTC

    You should investigate what kind query analysis tools your DBMS has.

    In particular, check your RDBMS docs for "EXPLAIN PLAN". It's how you get the database to cough up the query execution plan, which will tell you things like where the database is having to do full table scans to satisfy your query. This'll give you suggestions about where indexes might help.

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