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Thread Table with grid performance
Thu, Jan 3 2008 11:08 AMPermanent Link

"Brian Kennedy"
Hello.  I have a very wide table (~150 fields).  In my application, I am
populating a grid using this wide table with a TDBISAMTable component.
However, I am only using about 40 of the fields from the table in the grid
(DevExpress QuantunGrid).

My questions are:

1) I believe the answer is "YES", but just to clarify, is using the
TDBISAMTable component to fetch the 40 fields going to be slower than using
a limited field selection TDBISAMQuery?

2) Assuming #1 is "YES", lets say I use a TDBISAMQuery component and limit
the SELECT to 40 fields (SELECT field1, field2, field3, ...etc) to gain
performance.  However, there are many updates that occur to these fields at
the user level and from what I understand I would need to CLOSE and then
OPEN the query in order to refresh the data on the grid.  Correct?  If so,
this may not be any better...right?

3) Is there a way to make the TDBISAMTable component selection efficient
like the query by using persistent fields or by some other method?

Any other suggestions would greatly be appreciated...thank you!

Brian Kennedy
DBISAM C/S 4.24 B1


Fri, Jan 4 2008 7:45 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Brian,

<< 1) I believe the answer is "YES", but just to clarify, is using the
TDBISAMTable component to fetch the 40 fields going to be slower than using
a limited field selection TDBISAMQuery? >>

It depends upon the TDBISAMQuery.RequestLive property setting.  If it is
True, then the answer is no.  If it is False, then the answer is yes.

<< 2) Assuming #1 is "YES", lets say I use a TDBISAMQuery component and
limit the SELECT to 40 fields (SELECT field1, field2, field3, ...etc) to
gain performance.  However, there are many updates that occur to these
fields at the user level and from what I understand I would need to CLOSE
and then OPEN the query in order to refresh the data on the grid.  Correct?
>>

Correct.

<< If so, this may not be any better...right? >>

It really depends upon what the query has to do in terms of execution costs.

<< 3) Is there a way to make the TDBISAMTable component selection efficient
like the query by using persistent fields or by some other method? >>

No.

--
Tim Young
Elevate Software
www.elevatesoft.com

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