Re: Identifying indexes

Arup Nanda wrote:
>
> The only indexes that enforce a constaint are primary key and unique key
> indexes. You can easily spot them using
>
> SELECT INDEX_NAME, OWNER
> FROM DBA_INDEXES
> WHERE UNIQUENESS = 'NONUNIQUE'
>
> However, beware, there may be some unique indexes that may have been created
> for performance reasons only, even though a secondary intent may be to
> enforce a unique constraint. For instance Social Security Numbers are
> probably unique, guranteed pretty much by the application but an index
> defined on them will be defined as unique as unique indexes perform better.
> Therefore the intent here was not to enforce the constraint but rather to
> design a better index.
>
> HTH
>
> Arup Nanda

There may also be another problem, with indexes created on FKs to avoid deadlocks - not quite 'performance index' as usually accepted even if they cannot fully be considered as 'constraint indexes'. If you want to detect them, you have to check in DBA_IND_COLUMNS and DBA_CONS_COLUMNS - and I feel too lazy to write the query now.

-- 
Regards,

Stephane Faroult
Oriole Software
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Stephane Faroult
  INET: sfaroult_at_oriole.com

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