Comments on: Optimizing UPDATE Statements http://blogs.teamb.com/craigstuntz/2007/09/18/37753/ News of interest to Delphi, .NET, and InterBase programmers Sat, 22 Nov 2008 15:58:41 +0000 http://wordpress.org/?v=2.6.2 By: Craig Stuntz http://blogs.teamb.com/craigstuntz/2007/09/18/37753/#comment-614 Craig Stuntz Thu, 20 Sep 2007 13:05:15 +0000 http://blogs.teamb.com/craigstuntz/2007/09/18/37753#comment-614 Maxim and Romkin, Yes, I understand why the DSP/resolver generated the WHERE clause. Like I said in the post, it's beyond the scope of the post to discuss it here, but IMHO what it's doing is a *good* thing, and I don't want to stop it from doing that. The important point here is that the WHERE clause was legitimate, and the VIEW needed to be changed so that it could be executed quickly. Maxim and Romkin,

Yes, I understand why the DSP/resolver generated the WHERE clause. Like I said in the post, it’s beyond the scope of the post to discuss it here, but IMHO what it’s doing is a *good* thing, and I don’t want to stop it from doing that.

The important point here is that the WHERE clause was legitimate, and the VIEW needed to be changed so that it could be executed quickly.

]]> By: Romkin http://blogs.teamb.com/craigstuntz/2007/09/18/37753/#comment-611 Romkin Thu, 20 Sep 2007 08:31:52 +0000 http://blogs.teamb.com/craigstuntz/2007/09/18/37753#comment-611 NB: The where clause in update (and delete) statement, generated by SQL resolver may be controlled by TDatasetProvider.UpdateMode value. upWhereKeyOnly - all you needs for only primary key fields in 'where'. Exactly, TxxxQuery fields with pfInKey in ProviderFlags option only. NB:
The where clause in update (and delete) statement, generated by SQL resolver may be controlled by TDatasetProvider.UpdateMode value. upWhereKeyOnly - all you needs for only primary key fields in ‘where’. Exactly, TxxxQuery fields with pfInKey in ProviderFlags option only.

]]> By: Maxim http://blogs.teamb.com/craigstuntz/2007/09/18/37753/#comment-608 Maxim Thu, 20 Sep 2007 06:40:42 +0000 http://blogs.teamb.com/craigstuntz/2007/09/18/37753#comment-608 Or you can just set the DataSetProvider.UpdateMode to upWhereKeyOnly and include pfInKey into the PK field of the corresponding dataset. Then the provider will generate WHERE statement with PK field only. But upWhereAll or upWhereChanged are used to guard against update of a record that is already changed by a different user. So changing the view behaviour can lead to some sort of inconsistency between application developer expectations and actual database behaviour. Or you can just set the DataSetProvider.UpdateMode to upWhereKeyOnly and include pfInKey into the PK field of the corresponding dataset. Then the provider will generate WHERE statement with PK field only. But upWhereAll or upWhereChanged are used to guard against update of a record that is already changed by a different user. So changing the view behaviour can lead to some sort of inconsistency between application developer expectations and actual database behaviour.

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