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VIEWS vs FILTER
Message
From
16/11/1998 15:03:19
Ian Matthews
Up & Running Technologies Inc
Chestermere, Alberta, Canada
 
 
To
16/11/1998 14:54:26
General information
Forum:
Visual FoxPro
Category:
Coding, syntax & commands
Title:
Miscellaneous
Thread ID:
00157948
Message ID:
00157955
Views:
19
Thanks for the info.

re #2 - Do you have any specs or anecdotel evidence on how much faster VIEW's are than the FILTER command? I am trying to decide if I should rewrite:
- all my parent/child stuff;
- just my parent/child grid stuff, or;
- the parent/child code for the grid the one grid I am having probs with.


>>In a previous thread for a related topic, the clear concensus was that Parameratized Views are better than the FILTER command. I have three (simple?) questions about View's vs Filter that I can not locate documentation on.
>>
>>1: I am writing for a shared environment. I thought (from FP2.6) that SELECT (or any other SQL) could not be used in a networked/shared environment because it required Exclusive access. I created a test and noticed that the EXCLUSIVE property in my TESTVIEW was set to YES but my tests on my LAN seem to indicate that this is not a problem. I think EXCLUSIVE in this case relates to the VIEW, which is specific to each machine and therefore does not cause a problem (i.e. the use has exclusive access to a file(view) which is only on their machine anyway). Are there any networking issues I should be aware of with SELECT?
>
>Actually, there are no problems here. Make sure that tables already opened when you fire SELECT-SQL (just a precaution). Exclusive usage is really applied to view only.
>
>>2: As almost everyone has pointed out, it appears that the p-view is very fast. Is it faster that FILTER in all/most parent/child circumstances or is it just faster for grids? Basically, I am trying to decide if I should adjust the code for five large and complex main forms I already have written.
>
>It's mostly grid's problem. Other things depend on way you develop your application.
>
>>3: I found that unless I set SEND SQL UPDATES on in the View Designer, that the updates did not get sent to the base table. I was using TABLEBUFFER = 3-OPTIMISTIC ROW BUFFERING, and TABLEUPDATE(.T.) in my SKIPx commands. I think the TABLEUPDATE only updated the TESTVIEW info with its related cursor info. Is there anything I am missing here or is SEND SQL UPDATES the only thing I need to know?
>
>Yes, 'SendUpdates' is a requirement. Buffering setting handles how updates will be send to tables.
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