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From "Teresa Kan (JIRA)" <j...@apache.org>
Subject [jira] Updated: (OPENJPA-338) Remove unnecessary CAST in SQL statement for DB2
Date Mon, 27 Aug 2007 14:31:30 GMT

     [ https://issues.apache.org/jira/browse/OPENJPA-338?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Teresa Kan updated OPENJPA-338:
-------------------------------

    Attachment: OPENJPA-338.patch

Attach the patch and end result conversion for DB2 in various SQL functions.

> Remove unnecessary CAST in SQL statement for DB2
> ------------------------------------------------
>
>                 Key: OPENJPA-338
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-338
>             Project: OpenJPA
>          Issue Type: Improvement
>          Components: sql
>    Affects Versions: 1.0.0
>         Environment: Window XP, JDK 1.5
>            Reporter: Teresa Kan
>             Fix For: 1.0.1
>
>         Attachments: OPENJPA-338.patch
>
>
> There were unnecessary CAST added to the SQL statements that can be removed to improve
the performance. The change will eliminate the CAST for the constants. For example, the original
query is :
> Executing query: select d from DogABS d where LENGTH(d.name) < 10
> The current generated SQL statement:
> executing prepstmnt 1335250838 SELECT t0.id2, t0.datastoreid, t0.domestic, t0.name, t0.price,
t0.total FROM DOGABS t0 WHERE (CAST(LENGTH(CAST(t0.name AS VARCHAR(1000))) AS BIGINT) <
CAST(? AS BIGINT))  [params=(long) 10]
> After the changes:
> executing prepstmnt 1749706826 SELECT t0.id2, t0.datastoreid, t0.domestic, t0.name, t0.price,
t0.total FROM DOGABS t0 WHERE (LENGTH(t0.name) < ?)  [params=(long) 10]

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