Ggtcf

I am trying to create a simple object to handle all my database related functions. I have a functions to return a dataset or to execute a command. Now when i call this from my program I am able to fetch records using Execute_Dataset and it works fine but when i do an changes and execute a command by calling Execute_Command i get an error "database is locked" when the commit transaction is called. I have tried everything that i could be it still happens. Can someone put some light into what i am doing wrong and how i can prevent this from happening.

 function TConnectionManager.Execute_Dataset(const ASql: string; const AParams:
 array of variant; out VDataset: TDataset; const ATrn_Name: string): Boolean;
 var
 lTrn: TFDTransaction;
 lQry: TFDQuery;
 begin
 Result := True;
 lTrn:= TFDTransaction.Create (Self);
 try
 lTrn.Connection := FConnection;
 lTrn.StartTransaction;
 lQry := TFDQuery.Create (Self);
 lQry.Connection := FConnection;
 lQry.Transaction := lTrn;
 try
 if Length (AParams) > 0
 then lQry.Open (ASql, AParams)
 else lQry.Open (ASql);
 VDataset := lQry;
 Result := True;
 Commit transaction if started within the procedure 
 lTrn.Commit;
 except
 on e:Exception
 do begin
 Rollback transaction if started within the procedure 
 lTrn.Rollback;
 lQry.DisposeOf;
 //log
 raise;
 end;
 end;
 finally
 lTrn.DisposeOf;
 end;
 end;



 procedure TConnectionManager.Execute_Command(const ASql: string; const AParams:
 array of variant; const ATrn_Name: string);
 var
 lTrn: TFDTransaction;
 lQry: TFDQuery;
 begin
 lTrn:= TFDTransaction.Create (Self);
 try
 lTrn.Connection := FConnection;
 lTrn.StartTransaction;
 lQry := TFDQuery.Create (Self);
 lQry.Connection := FConnection;
 lQry.Transaction := lTrn;
 try
 Execute command 
 if Length (AParams) > 0
 then lQry.ExecSQL (ASql, AParams)
 else lQry.ExecSQL (ASql);
 Commit transaction if started within the procedure 
 lTrn.Commit;
 except
 on e:Exception
 do begin
 Rollback transaction if started within the procedure 
 lTrn.Rollback;
 //log
 raise;
 end;
 end;
 finally
 lQry.DisposeOf;
 lTrn.DisposeOf;
 end;
 end;

Thanks

Try setting the Connection's properties SharedCache to 'False' and LockingMode to 'Normal'.

The default value for the connection's locking mode is 'exclusive' which can cause this problem. You can do this by right clicking on your Connection-Component (on the form) and choosing ConnectionEditor (I'm not quite sure, if that's the right English word for it, but it should be called something like that) and then setting these values.

Alternatively you can set these properties in sourcecode:

connection.Params.Add('SharedCache=False');
connection.Params.Add('LockingMode=Normal');

I'm not sure that this is the best way to solve this problem. There might be a better solution to this.

Because other connection exist. Check connection component in datamodule
MyFDConnection.Connected:=False;