c# - 将命令文本转换为已回答问题中的字符串问题

Question

与这篇文章相关的问题，我认为他离线了，所以我无法在atm上得到任何反馈: MySql and inserting last ID problem remains我不确定我是否完全失明，但在这段代码中:

            // run the insert using a non query call
            command.CommandText = cmd.ToString();
            command.ExecuteNonQuery();

            /* now we want to make a second call to MYSQL to get the new index 
               value it created for the primary key.  This is called using scalar so it will
                return the value of the SQL  statement.  We convert that to an int for later use.*/
            command.CommandText = "select last_insert_id();";
            id = Convert.ToInt32(command.ExecuteScalar());

            //------- the name id does not exist in the current context

            // Commit the transaction.
            transaction.Commit();
        }
        catch (Exception ex)
        {
            Label10.Text = ": " + ex.Message;

            try
            {
                // Attempt to roll back the transaction.
                transaction.Rollback();
            }
            catch
            {
                // Do nothing here; transaction is not active.
            }
        }
    }

id 没有设置任何内容，我不确定他是如何尝试将其设置为最后插入的 id？

编辑:

int id = Convert.ToInt32(cmd.ExecuteScalar());
Label10.Text = Convert.ToString(id);

Answer 1

您应该能够使用 select @@IDENTITY; 返回插入记录的 ID，而无需使用第二个查询:

 OdbcCommand cmd = new OdbcCommand("INSERT INTO User (Email) VALUES ('rusty@msn.com'); select @@IDENTITY;"
 int id = Convert.ToInt32(cmd.ExecuteScalar());

查看您的旧问题后，这应该起到相同的作用:

 OdbcCommand cmd = new OdbcCommand("INSERT INTO User (Email) VALUES ('rusty@msn.com'); SELECT LAST_INSERT_ID();"
 int id = Convert.ToInt32(cmd.ExecuteScalar());