mysql + unidac 使用事务例子

//备注：mysql必须是使用innoDB引擎才支持事务功能，否则以下事务相关代码将失效。//SQL SERVER和Oracle还没试，明天回公司试了再发代码。procedure TForm1.btn1Click(Sender: TObject);

var

  i, j: Integer;

begin

  UniConnection1.Connect;

  try

    try

      UniTransaction1.Connections[0].StartTransaction;

      UniQuery1.Params.Clear;

      UniQuery1.SQL.Text := 'insert into user (username,password)values(:username, :password)';

      UniQuery1.Params.ParamByName('username').Value := 'eboy';

      UniQuery1.Params.ParamByName('password').Value := '1111';

      UniQuery1.ExecSQL; //如果不使用事务，这条将插入进去



      UniQuery1.Params.Clear;

      UniQuery1.SQL.Text := 'insert into user (username,password)values(:username, :password)';

      UniQuery1.Params.ParamByName('username').Value := 'frr';

      UniQuery1.Params.ParamByName('password').Value := '123';

      UniQuery1.ExecSQL; //如果不使用事务，这条将插入进去



      UniQuery1.Params.Clear;

      UniQuery1.SQL.Text := 'insert into user (username,password)values(:username, :password)';

      UniQuery1.Params.ParamByName('username').Value := 'lj';

      UniQuery1.Params.ParamByName('password').Value := '880414';

      UniQuery1.ExecSQL; //如果不使用事务，这条将插入进去



      UniQuery1.Params.Clear;

      UniQuery1.SQL.Text := 'insert into user (username,password)values(:username, :password)';

      UniQuery1.Params.ParamByName('username').Value := 'lj';

      UniQuery1.Params.ParamByName('password').IsNull; //字段设为not null，所以这里会出错

      UniQuery1.ExecSQL; //开启事务后，上面的三条都将回滚

      

      UniTransaction1.Connections[0].Commit;



    except on e: Exception do

      begin

        UniTransaction1.Connections[0].Rollback;

        ShowMessage(e.Message);

      end;

    end;  

  finally

    UniConnection1.Disconnect;

  end;

end;