Hi,

For performance issue I am trying to save a TEDBTable to a TMemoryStream using "SaveToStream" method and loading it into a TClientDataSet using "LoadFromStream" but with no luck (I get an error in loading the stream)!  First thing comes to my mind, is EDB compatible with Delphi stream?
Regards,
Abdulaziz Jasser

Yes

A very trivial example would be something like this:

var
  str:TMemoryStream;
begin
  EDBTableSrc.TableName := 'SOURCETBL';
  EDBTableDest.TableName := 'DESTTBL';

  //open both
  EDBTableSrc.Active := true;
  EDBTableDest.Active := true;

  str := TMemoryStream.Create;
  try
    EDBTableSrc.SaveToStream(str);
    EDBTableDest.LoadFromStream(str);
  finally
    str.Free;
  end;

  EDBTableSrc.Active := false;
  EDBTableDest.Active := false;
end;

Raul

On 7/25/2012 11:04 AM, Abdulaziz Jasser wrote:
> Hi,
>
> For performance issue I am trying to save a TEDBTable to a TMemoryStream using "SaveToStream" method and loading it into a TClientDataSet using "LoadFromStream" but with no luck (I get an error in loading the stream)!  First thing comes to my mind, is EDB compatible with Delphi stream?
> Regards,
> Abdulaziz Jasser
>

Raul,

How about if change the destination table form TEDBTable to TClientDataSet?  Would it work?
Regards,
Abdulaziz Jasser

Raul,

Ok... the issue is solved.  My code was missing "CreateDataSet" method.  Thanks.
Regards,
Abdulaziz Jasser

Sorry - missed the TClientDataSet part.

No - EDB and TClientDataSet are 2 completely different DB engines and
streams are not compatible (same way EDB and DBISAM streams would not be
compatible).

If you look at their class hierarchy then only common ancestor is
TDataSet and unfortunately it does not implement
LoadFromStream/SaveToStream so those function are specific to each side.

If you need to be able to exchange data between EDB and TClientDataSet
then you need to do it at the TDataSet level:
- basically obtain 2 TDataSets and then run a dual-loop over them (one
from 1st record to last and other thru fields for each row) and copy
data field by field.

Raul


On 7/25/2012 3:03 PM, Abdulaziz Jasser wrote:
> Raul,
>
> How about if change the destination table form TEDBTable to TClientDataSet?  Would it work?
> Regards,
> Abdulaziz Jasser
>

Raul,

<<If you need to be able to exchange data between EDB and TClientDataSet
then you need to do it at the TDataSet level:
- basically obtain 2 TDataSets and then run a dual-loop over them (one
from 1st record to last and other thru fields for each row) and copy
data field by field.>>

That would be slow over a slow internet connection.  I am looking for a method to move the data to the client pc and then loop the data localy.
Regards,
Abdulaziz Jasser

Then just use the EDB on both sides - you can use it in pure in-memory
mode.

Raul


On 7/25/2012 5:19 PM, Abdulaziz Jasser wrote:
> Raul,
>
> <<If you need to be able to exchange data between EDB and TClientDataSet
> then you need to do it at the TDataSet level:
> - basically obtain 2 TDataSets and then run a dual-loop over them (one
> from 1st record to last and other thru fields for each row) and copy
> data field by field.>>
>
> That would be slow over a slow internet connection.  I am looking for a method to move the data to the client pc and then loop the data localy.
> Regards,
> Abdulaziz Jasser
>

Raul wrote:

<<Then just use the EDB on both sides - you can use it in pure in-memory mode.>>

I think you got my point.  Can you point me to who to create a local table which will load the stream from the remote database?
Regards,
Abdulaziz Jasser

The basic idea is to simply have 2 sessions in your application - one
local and one remote. You would do the SaveToStream from remote EDBtable
and then run the LoadFromStream on the local EDBTable.

Check out the UseLocalSessionengineSettings option of the engine
http://www.elevatesoft.com/manual?action=viewprop&id=edb2&product=rsdelphiwin32uni&version=XE2&comp=TEDBEngine&prop=UseLocalSessionEngineSettings

You might also be interested in the ConfigMemory property:
http://www.elevatesoft.com/manual?action=viewprop&id=edb2&product=rsdelphiwin32uni&version=XE2&comp=TEDBEngine&prop=ConfigMemory


When you are creating the local database then just specify IN MEMORY as
the path
http://www.elevatesoft.com/manual?action=viewtopic&id=edb2sql&topic=CREATE_DATABASE

Raul



On 7/25/2012 6:24 PM, Abdulaziz Jasser wrote:
> I think you got my point.  Can you point me to who to create a local table which will load the stream from the remote database?
> Regards,
> Abdulaziz Jasser
>