if not indicate id_master the query must scroll all id_master (then the
entire archive) so you better define the index: CREATE UNIQUE INDEX ON
UNQ_DETAILS_DATA DETAILS_DATA (ID_PARAM, ID_MASTER) to limit your search to
only id_param = 60 with query where id_param = 60. greetings




-------Messaggio originale-------

Da: Virgo Pärna virgo.parna@... [firebird-support]
Data: 18/07/2015 8.02.41
A: firebird-support@yahoogroups.com
Oggetto: [firebird-support] Re: Is it possible to use only "part" of the
index?


On 17 Jul 2015 07:14:02 -0700, brucedickinson@... [firebird-support]
<firebird-support@yahoogroups.com> wrote:

> CREATE UNIQUE INDEX UNQ_DETAILS_DATA ON DETAILS_DATA (ID_MASTER,ID_PARAM);
>
> when performing this query:
>
> WHERE
> DD.ID_PARAM = 60
>

ID_PARAM is second field in the index. So the index cannot be used,
because it would need to check all ID_MASTER values anyway.

--
Virgo Pärna
virgo.parna@...





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