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Thread BLOB handling for client
Tue, Oct 31 2006 7:21 PMPermanent Link

"Glynn Owen"
Jason Lee wrote:

> You can use the same query, just don't display the blob field in your
> grid initially....(hint: double-click the dbgrid at design-time to
> get a field list)
>
> Glynn Owen wrote:
> > Yes, but that seems to be throwing out the baby with the bathwater.
> > I'm trying to avoid doing a second query just to fetch the blob
> > field.

The field list changes at the operator's request. There is no fixed
list of fields.

Thanks anyway,
Glynn
Wed, Nov 1 2006 1:02 PMPermanent Link

"Glynn Owen"
Glynn Owen wrote:

> I need to have my server send blobs to a client. I would like to do
> this so that the client doesn't receive the contents of any blob until
> those contents are specifically requested. I'm using TDBISAMQuery
> components for the data transfer. I have a primary table on display
> with a lot of controls that allow for user-defined queries.
>
> I could put the blobs in a separate table linked by a key to the
> primary table, and then run a separate query on request, but I'm
> wondering if there might be a better way to do this. Any suggestions
> would be welcome.
>
> TIA, Glynn

I hooked the AfterOpen event of the query and set the blob fields'
visibility to FALSE. It appears to do exactly what I hoped. Thanks for
all the help.

Regards,
Glynn
Wed, Nov 1 2006 7:15 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Glynn,

<< The field list changes at the operator's request. There is no fixed list
of fields. >>

Do you allow the user to select BLOB fields for display ?  The reason that
I'm asking is that with a normal TDBGrid, then don't actually display
anything except NULL indication.

--
Tim Young
Elevate Software
www.elevatesoft.com

Wed, Nov 1 2006 9:07 PMPermanent Link

"Glynn Owen"
Tim Young [Elevate Software] wrote:

> Glynn,
>
> << The field list changes at the operator's request. There is no
> fixed list of fields. >>
>
> Do you allow the user to select BLOB fields for display ?  The reason
> that I'm asking is that with a normal TDBGrid, then don't actually
> display anything except NULL indication.

Not exactly. It's just that, regardless of what the user can see in the
grid (and that does *not* include the blob field), the user has the
option of viewing the contents of the blob by pushing a button. The
solution I mentioned seems to work just fine. I make sure that the blob
field is included in any query, but in the AfterOpen event of the
query, I make the blob field invisible. The blob field does not
display, but when (or if) the button gets pressed, I can access the
blob field in code and display the result to the user. It seems to work
just like I had hoped.

Excellent product you have here. I can't imagine what took me so long
to find it. I was really amazed that hooking up to a database in a
different country was so easy.

Thanks for your help,
Glynn
Thu, Nov 2 2006 10:47 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

Avatar

Email timyoung@elevatesoft.com

Glynn,

<< Not exactly. It's just that, regardless of what the user can see in the
grid (and that does *not* include the blob field), the user has the option
of viewing the contents of the blob by pushing a button. The solution I
mentioned seems to work just fine. I make sure that the blob field is
included in any query, but in the AfterOpen event of the query, I make the
blob field invisible. The blob field does not display, but when (or if) the
button gets pressed, I can access the blob field in code and display the
result to the user. It seems to work just like I had hoped. >>

Ahh, now I understand what you're doing.  Sometimes it takes me a little bit
of time, but eventually I get it. Smiley

<< Excellent product you have here. I can't imagine what took me so long to
find it. I was really amazed that hooking up to a database in a different
country was so easy. >>

Thanks - tell your friends. Smiley

--
Tim Young
Elevate Software
www.elevatesoft.com

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