RE: Create View

Birgitta,

Thanks for the correction.

I was obvious working under the wrong impression.

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
 

> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx
> [mailto:midrange-l-bounces@xxxxxxxxxxxx]On Behalf Of Hauser, Birgitta
> Sent: Tuesday, August 02, 2005 9:28 AM
> To: 'Midrange Systems Technical Discussion'
> Subject: AW: Create View
> 
> 
> I don't that a MQT will be a good solution:
> 
> The automatic update for a MQT is not yet realized.
> That means it must be manually refreshed.
> Because the refresh performs a CLRPFM and a lot of writes into the MQT
> (physical table). This will more expensive than using a view or a UTF.
> 
> From: The creation and use of materialized query tables 
>       within IBM DB2 UDB for iSeries by Michael Caine
> "DB2 UDB for iSeries does not automatically keep materialized 
> query tables
> synchronized with the base tables. When the base tables are 
> changing due to
> insert, update or delete activity, there can be a difference 
> between the
> contents of the MQT(s) and the contents of the base tables. 
> This difference
> represents the data latency.
> 
> It is the responsibility of the user or programmer to refresh 
> or maintain
> the MQT data. If user queries are accessing MQTs and the 
> MQT(s) are not
> maintained as the base table(s) change, the query results 
> will increasingly
> diverge away from the results obtained from querying the base tables
> directly."
> 
> For more information about MQT read:
> The creation and use of materialized query tables within IBM 
> DB2 UDB for
> iSeries by Michael Caine
> http://www-1.ibm.com/servers/enable/site/education/abstracts/4
> 38a_abs.html
> 
> Birgitta
> 
> Mit freundlichen Grüßen
>  
> i.A. Birgitta Hauser
>  
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