Question

When i Run this code in a 32 bits delphi application the connection to MySql is successfully established.

{$APPTYPE CONSOLE}

{$R *.res}

uses
  AdoDb,
  ActiveX,
  SysUtils;

Var
  LConn : TADOConnection;
begin
  try
    CoInitialize(nil);
    try
      LConn:=TADOConnection.Create(nil);
      try
        LConn.ConnectionString:='Driver={MySQL ODBC 5.1 Driver};Server=127.0.0.1;Database=mysql;User=*****; Password=*****;Option=3';
        LConn.Connected:=True;
        Writeln('Connected');
      finally
        LConn.Free;
      end;
    finally
      CoUninitialize;
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
  Readln;
end.

But the same code code fails with this exception

EOleException: [Microsoft][ODBC Driver Manager] Data source name not
found and no default driver specified

If the code is compiled as a 64 bits application. the question is Why the same code fails in the 64 bits application?

Answer 1

To avoid this exception you must install the MySQL ODBC driver for 64 bits.