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EugeneE · Beginner Joined: 24 Apr 2005 Posts: 8 Topics: 3

Hi,

Our application interactively executes a complex SELECT from DB2 (v 7.1). Execution takes about 1 min.

I am thinking of creating a VIEW, based on this select and execute select * from thic VIEW. I do not understand how VIEW is working. Will the original select be executed every time when I obtain data from the VIEW? Or the VIEW will be updated when the data in the original tables was updated?

The original tables are updated in batch, so if the VIEW will be updated in the same time, the interactive execution will be fast.

Can somebody help me out please?

Thank you

s_shivaraj · Posted: Sun Apr 24, 2005 11:54 pm Post subject:

EugeneE,

I didnt think your execution time will reduce because of creating a VIEW, because your query is executed every time over the table even when u create a VIEW and VIEW wouldnt store the query results seperately anywere.

kolusu · Posted: Mon Apr 25, 2005 7:51 am Post subject:

EugeneE,

Please check this link which explains in detail about Views

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DSNSQH10/1.12?DT=20010215120247

Hope this helps...

Cheers

Kolusu
_________________
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EugeneE · Beginner Joined: 24 Apr 2005 Posts: 8 Topics: 3

Thank you very much, now it is clear.

Does mainframe DB2 have something like materialized queries or anything else to populate at batch time?

Thank you

kolusu · Posted: Tue Apr 26, 2005 7:37 am Post subject:

CZerfas · Intermediate Joined: 31 Jan 2003 Posts: 211 Topics: 8

In DB2 version 8 (on z/OS) you will have MQTs (materialized query tables), which will perform as you asked. There population can be triggered via the new REFRESH TABLE statement.

regards
Christian

EugeneE · Beginner Joined: 24 Apr 2005 Posts: 8 Topics: 3

Thank you Christian, will wait for version 8