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<title>dbm 类数据库函数库</title>
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<td valign=middle nowrap><font color=e06060 size=+2><b>dbm 类数据库函数库</b></font></td>
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<div align=right>本函数库共有 10 个函数</div><p><table border=0 cellpadding=12 cellspacing=0><tr><td bgcolor=e0e0ff>dbm 为柏克莱大学所发展的文件型数据库。欲使用本函数可能需要先安装相关的 DBM 函数馆,当然在 BSD 系列的操作系统中已经装好的就不用自行动手了。<p>

dbm 在资料存取没有很复杂的字段,它只有单纯的键/值 (key/value) 的字段。<p>

下例为简单的 dbm 使用范例<p>

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<font color="#0000BB">&lt;?<br></font><font color="#007700">function&nbsp;</font><font color="#0000BB">do_stuff</font><font color="#007700">()&nbsp;{<br>&nbsp;&nbsp;</font><font color="#FF8000">//&nbsp;略去复杂的资料处理流程<br></font><font color="#007700">}<br></font><font color="#0000BB">$dbm&nbsp;</font><font color="#007700">=&nbsp;</font><font color="#0000BB">dbmopen</font><font color="#007700">(</font><font color="#DD0000">"lastseen"</font><font color="#007700">,&nbsp;</font><font color="#DD0000">"w"</font><font color="#007700">);<br>if&nbsp;(</font><font color="#0000BB">dbmexists</font><font color="#007700">(</font><font color="#0000BB">$dbm</font><font color="#007700">,&nbsp;</font><font color="#0000BB">$userid</font><font color="#007700">))&nbsp;{<br>&nbsp;&nbsp;</font><font color="#0000BB">$last_seen&nbsp;</font><font color="#007700">=&nbsp;</font><font color="#0000BB">dbmfetch</font><font color="#007700">(</font><font color="#0000BB">$dbm</font><font color="#007700">,&nbsp;</font><font color="#0000BB">$userid</font><font color="#007700">);<br>}&nbsp;else&nbsp;{<br>&nbsp;&nbsp;</font><font color="#0000BB">dbminsert</font><font color="#007700">(</font><font color="#0000BB">$dbm</font><font color="#007700">,&nbsp;</font><font color="#0000BB">$userid</font><font color="#007700">,&nbsp;</font><font color="#0000BB">time</font><font color="#007700">());<br>}<br></font><font color="#0000BB">do_stuff</font><font color="#007700">();<br></font><font color="#0000BB">dbmreplace</font><font color="#007700">(</font><font color="#0000BB">$dbm</font><font color="#007700">,&nbsp;</font><font color="#0000BB">$userid</font><font color="#007700">,&nbsp;</font><font color="#0000BB">time</font><font color="#007700">());<br></font><font color="#0000BB">dbmclose</font><font color="#007700">(</font><font color="#0000BB">$dbm</font><font color="#007700">);<br></font><font color="#0000BB">?&gt;<br></font>
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<table border=0 width=100%><tr><td align=right valign=top><a href="function.php-dbmopen.htm" alt="function.php?dbmopen">dbmopen</a>:</td><td valign=top>打开 DBM 数据库链接。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmclose.htm" alt="function.php?dbmclose">dbmclose</a>:</td><td valign=top>关闭 DBM 数据库。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmexists.htm" alt="function.php?dbmexists">dbmexists</a>:</td><td valign=top>检查键是否存在。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmfetch.htm" alt="function.php?dbmfetch">dbmfetch</a>:</td><td valign=top>取回指定资料。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbminsert.htm" alt="function.php?dbminsert">dbminsert</a>:</td><td valign=top>加入资料。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmreplace.htm" alt="function.php?dbmreplace">dbmreplace</a>:</td><td valign=top>改动或加入资料。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmdelete.htm" alt="function.php?dbmdelete">dbmdelete</a>:</td><td valign=top>删除指定资料。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmfirstkey.htm" alt="function.php?dbmfirstkey">dbmfirstkey</a>:</td><td valign=top>取回首笔键名。</td></tr>
<tr><td align=right valign=top><a href="function.php-dbmnextkey.htm" alt="function.php?dbmnextkey">dbmnextkey</a>:</td><td valign=top>取回下笔键值。</td></tr>
<tr><td align=right valign=top><a href="function.php-dblist.htm" alt="function.php?dblist">dblist</a>:</td><td valign=top>取得 DBM 的信息。</td></tr>
</table><p><hr size=1><br>如果你对此手册有任何问题,请到下面网址提问:&nbsp;<a href="www.web745.com">WEB开发知识库</a>&nbsp;(<a href="http://www.web745.com">www.web745.com</a>)<p>
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