打造PHP的无限分级类(完整代码及注释)_PHP教程

<OL class=dp-sql><LI class=alt><SPAN><SPAN class=keyword>CREATE</SPAN><SPAN> </SPAN><SPAN class=keyword>TABLE</SPAN><SPAN> `b_mtype` (  </SPAN></SPAN><LI class=""><SPAN>  `typeid` </SPAN><SPAN class=keyword>int</SPAN><SPAN>(4) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>'0'</SPAN><SPAN>,  </SPAN></SPAN><LI class=alt><SPAN>  `typename` </SPAN><SPAN class=keyword>varchar</SPAN><SPAN>(50) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>''</SPAN><SPAN>,  </SPAN></SPAN><LI class=""><SPAN>  `parentid` </SPAN><SPAN class=keyword>int</SPAN><SPAN>(4) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>'0'</SPAN><SPAN>,  </SPAN></SPAN><LI class=alt><SPAN>  `parentstr` </SPAN><SPAN class=keyword>varchar</SPAN><SPAN>(200) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>''</SPAN><SPAN>,  </SPAN></SPAN><LI class=""><SPAN>  `depth` </SPAN><SPAN class=keyword>int</SPAN><SPAN>(4) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>'0'</SPAN><SPAN>,  </SPAN></SPAN><LI class=alt><SPAN>  `rootid` </SPAN><SPAN class=keyword>int</SPAN><SPAN>(4) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>'0'</SPAN><SPAN>,  </SPAN></SPAN><LI class=""><SPAN>  `child` </SPAN><SPAN class=keyword>varchar</SPAN><SPAN>(200) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>''</SPAN><SPAN>,  </SPAN></SPAN><LI class=alt><SPAN>  `orders` </SPAN><SPAN class=keyword>varchar</SPAN><SPAN>(200) </SPAN><SPAN class=op>NOT</SPAN><SPAN> </SPAN><SPAN class=op>NULL</SPAN><SPAN> </SPAN><SPAN class=keyword>default</SPAN><SPAN> </SPAN><SPAN class=string>''</SPAN><SPAN>,  </SPAN></SPAN><LI class=""><SPAN>  </SPAN><SPAN class=keyword>PRIMARY</SPAN><SPAN> </SPAN><SPAN class=keyword>KEY</SPAN><SPAN>  (`typeid`)  </SPAN></SPAN><LI class=alt><SPAN>) TYPE=MyISAM;  </SPAN><LI class=""><SPAN> </SPAN></LI></OL>