Subject AW: [firebird-support] Litte question about indexes
Author Olaf Kluge
Thank you Ann.





On Fri, May 31, 2013 at 2:50 AM, Olaf Kluge <olaf.kluge@...
<mailto:olaf.kluge%40satron.de> > wrote:

>
> in a table A there is a primary key, one column named ID. The second table
> B
> uses a single Field named ID_TableA, it references to the Table A (foreign
> key) and this field is the primary key too. (1 to 1 relation). Now I have
> two indexes for one Table-Column. Is this an problem?
>

A 1:1 relationship suggests a problem with the data model, but probably
you've
got a good reason for separating the information. Having two indexes on
ID_TableA in table B will increase the cost of inserts, deletes, and
updates that
affect that column. If you need the foreign key constraint, there's no way
to
avoid a second index.

Good luck,

Ann
IBPhoenix Tech Consultant

column more expensive

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> Best regards.
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> Olaf
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