Subject Re: [IBO] TIB_Query.ColumnAttributes -->MyComputedColumn=computed
Author Jason Wharton
Actually, I need to correct some things here.

The COMPUTED column attribute is intended exactly for columns in a table
that are COMPUTED BY derived. Otherwise, IBO doesn't know how to tell them
apart from the other normal columns.

If a field in a select is a derived calculation IBO will know that it is
calculated without you having to flag it as COMPUTED in the ColumnAttributes
property. This is because it won't return anything in the RelName or SQLName
portions of the column descriptors. It will only have the AliasName filled
in depending on what you named the column.

HTH,
Jason Wharton
CPS - Mesa AZ
http://www.ibobjects.com


----- Original Message -----
From: "Helen Borrie" <helebor@...>
To: <IBObjects@yahoogroups.com>
Sent: Friday, April 06, 2001 5:41 AM
Subject: Re: [IBO] TIB_Query.ColumnAttributes -->MyComputedColumn=computed


> At 02:02 PM 06-04-01 +0200, you wrote:
> >Hi,
> >
> >I have a computed by column in a IB table.
> >In TIB_Query.ColumnAttributes I can setup
> >"MyComputedColumn"=computed.
> >
> >I really dont see a difference, when I set
> >or not set this computed attribute.
> >
> >Anyone knows for what it was intended ?
>
> It's not intended for columns that exist in the database (such as a
COMPUTED BY column or any regular column) - it is for non-database columns
that are computed by a query, i.e expressions and subselects that output as
if they were columns...also for CalculatedFields. Its purpose is to tell
the parser not to try to match it to a database column for e.g. a WHERE
criterion.
>
> hth
> Helen
>
> >Thanks
> >Harald Klomann
> >