Question

I am having a Database connected application.
Connected using BDE components and database is MySQL.

Now I am doing some validations for checking if duplicate entry while insert statement is executed.

The following is the code to check if duplicate entry for primary key attribute .

var
  error :string; 
  cmpres:integer;
begin
 ...
 /* all my data queries */
  try
    Query1.ExecSQL;
  Except
   on E: Exception do
   /*check if its a Duplicate entry or other exception*/
    begin    
         error := E.Message;
         error := copy(error,length(error)-16,length(error)-2);
         cmpres :=CompareStr(LowerCase(error),'for key '+#39+'primary'+#39) ;
         if cmpres = 0  then
           MessageDlg('Entry already exist',mtError,[mbok],0)
         else
           MessageDlg('Invalid Data Entries',mtError,[mbok],0);
         exit;
    end;
  end;
end; 

The database exceptions are broadly put inside EDatabaseError

Can anyone tell me is there any way I can differentiate between these errors without doing the Message comparisons.
Thanks in advance

Answer 1

If you’re using BDE, the exceptions should be EDBEngineError, not EDatabaseError. You can do this:

try
    Query1.ExecSQL;
except
    on E: EDBEngineError do
    begin
        for i := 0 to E.ErrorCount - 1 do
        begin
            err := E.Errors[i];
            case err.ErrorCode of
                ... stuff ...
            end;
        end
    end;
end