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From Mark Thornton <mthorn...@optrak.co.uk>
Subject Re: Creating multiple indexes with different names on the same column does nothing.
Date Sat, 01 Nov 2008 09:00:59 GMT
David Van Couvering wrote:
> I noticed that if you try to create two indexes with different names 
> on the same column set that Derby silently ignores the command.
>
> I can understand the rationale - it doesn't make sense to maintain two 
> keys against the same columns - they're the same key.  But it would be 
> useful to say something that lets the user know that the index already 
> exists, rather than silently succeeding.
>
One case where two indexes on the same column does make sense is if you 
are permitted to specify different collations for each index. Thus with 
a table of place names you could have different indexes for each 
language that you choose to support. OK, Derby doesn't support this (I 
do in a special database used for geographical information).

Mark Thornton


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