一个事务的例子

protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection conn;
        SqlCommand cmd1, cmd2;
        SqlTransaction tra;
        conn = new SqlConnection("server=.;database=test;uid=sa;pwd=123");
        conn.Open();
        tra = conn.BeginTransaction();//开始事务
        cmd1 = new SqlCommand("update Test set StuName='佳儿' where StuScore=111", conn);
        cmd2 = new SqlCommand("update Test set StuName='fdsafdsafdsfdsafsfsdadsadsadfsafsfsfdf' where StuScore=222", conn);
        try
        {
            cmd1.ExecuteNonQuery();//此句可以成功执行
            cmd2.ExecuteNonQuery();//此句故意让其执行失败
            tra.Commit();//无异常，提交事务(两句执行都有效)
            Response.Write("<script>alert('执行成功')</script>");
        }
        catch
        {
            tra.Rollback();//出现异常，回滚事务(两句执行都无效)
            Response.Write("<script>alert('执行失败')</script>");
        }
        finally
        {
            conn.Close();
        }
    }