Problem copying entities from one DB to another

[Maierhofer_Bernd]

Hi + tx for any info.

I want to copy data from an MSSQL database to an SQLite database.

This is how I create the object managers:

function TmodelMain.CreateMSSQLManager: TObjectManager;
begin
  Result := TObjectManager.Create(conMSSQL.CreateConnection, TMappingExplorer.Get('Source'));
end;

function TmodelMain.CreateSQLiteManager: TObjectManager;
begin
  Result := TObjectManager.Create(conSQLite.CreateConnection, TMappingExplorer.Get('Target'));
end;

This is how I copy the data:

 for LebensmittelMSSQL in modelMain.GetLMCursor(nTotal) do begin
    modelMain.AddLebensmittelToSQLite(LebensmittelMSSQL);
  end;

Finally, the saving:

procedure TmodelMain.AddLebensmittelToSQLite(Lebensmittel: entityLebensmittel.TTBLLebensmittel);
begin
  mgrSQLite.Save(Lebensmittel);
end;

However, on destroying things,

procedure TmodelMain.DataModuleDestroy(Sender: TObject);
begin
  FreeAndNil(mgrMSSQL);
  FreeAndNil(mgrSQLite);
end;

freeing the mgrSQLite fails with an invalid pointer.

If I comment the line mgrSQLite.Save, freeing the managers succeeds. I think,the entity belongs now to both managers and this is why the second free fails, as it also tries to free the entity.

What am I doing wrong here?

Thanks for support!

[Maierhofer_Bernd]

Reread the docs. :- )

If I understand things right, the problem is, that both managers own the entity. So setting the OwnsObjects to false for one of the managers should solve the situation.

Is this correct?

[wlandgraf (Wagner Landgraf)]

Yes, that is correct.
Alternatively, instead of Save you can use Replicate method, which will create a copy of the object in the other manager.

Replicate is slower but better suited to migrate data, since it will not only create a new record if it doesn't exist, but also update existing records with the new data. It will also replicate all associated objects.

[Maierhofer_Bernd]

Thank you, Wagner, for the answer and the explanation.