MrSpock1

So far I have identified one problem: ExecSQL raises exception, so it does not come to commit when transactions overlap

Delphi, SQlite and dbExpress I open two copies of the app. I have one SQLConnection and two SQLQuery. SQLQuery1.SQL:=insert into topics(da,topic) values(1,'1') SQLQuery2.SQL:=insert into topics(da,topic) values(2,'2') there is a suspicious var Form1: TForm1; in the interface part, which I do not know how to remove In form.oncreate SQLConnection1.Connected:=true The first copy runs the first code Code: procedure TForm1.Button2Click(Sender: TObject); var tr: TTransactionDesc; finished: boolean; begin try SQLQuery2.SQLConnection:=SQLConnection1; SQLConnection1.StartTransaction(tr); SQLQuery2.ExecSQL; sleep(4000); SQLConnection1.Commit(tr); finished:= true; SQLQuery2.SQLConnection:=nil except SQLConnection1.Rollback(tr); finished:= false; end; if finished then showmessage('OK') else ShowMessage('NOT OK'); end; and the second copy runs the second code Code: procedure TForm1.Button3Click(Sender: TObject); var tr: TTransactionDesc; finished: boolean; begin repeat try SQLQuery3.SQLConnection:=SQLConnection1; SQLConnection1.StartTransaction(tr); SQLQuery3.ExecSQL; SQLConnection1.Commit(tr); finished:= true; SQLQuery3.SQLConnection:=nil; memo1.Lines.Add('OK') except sleep(400); SQLConnection1.Rollback(tr); finished:= false; memo1.Lines.Add('NOT OK') end; until finished; memo1.Lines.Add('END') end; When I run the codes one after another I get all right two records inserted into the database, but when I start the second code before the first transaction finishes, I get both OK messages but there appears only one record inserted in the database. The second transaction waits normally until the first finishes.