如果需要管理不同话题的多个会话，还需要建立一个表记录不同的话题，并在消息表中增加相关的topic_id。

If you want to manage multiple conversations on different topics, you must have another table to track the topics and include a related topic_id in the messages table.

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该整数是对系统错误消息表的索引，这个表名为sys_errlist(字符串数组)，其最高元素的索引为sys_nerr - 1。

This int is an index into a table of system error messages, called sys_errlist (an array of strings), whose highest element has index sys_nerr - 1.

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另请注意，除非您正在对允许用户输入电子邮件消息的表使用ssl，否则键入的任何内容都是明文形式的。

Also note that unless you're using SSL on the form that allows the user to enter the E-mail message, whatever is typed is in cleartext.

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