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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Examples</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="dba.constants.html">Predefined Constants</a></div> <div class="next" style="text-align: right; float: right;"><a href="ref.dba.html">DBA Functions</a></div> <div class="up"><a href="book.dba.html">DBA</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div> <h1>Examples</h1> <div id="dba.example" class="section"> <h2 class="title">Basic usage</h2> <p class="para"> <div class="example"> <p><b>Example #1 DBA example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /><br />$id </span><span style="color: #007700">= </span><span style="color: #0000BB">dba_open</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/test.db"</span><span style="color: #007700">, </span><span style="color: #DD0000">"n"</span><span style="color: #007700">, </span><span style="color: #DD0000">"db2"</span><span style="color: #007700">);<br /><br />if (!</span><span style="color: #0000BB">$id</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"dba_open failed\n"</span><span style="color: #007700">;<br /> exit;<br />}<br /><br /></span><span style="color: #0000BB">dba_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">"key"</span><span style="color: #007700">, </span><span style="color: #DD0000">"This is an example!"</span><span style="color: #007700">, </span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">dba_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">"key"</span><span style="color: #007700">, </span><span style="color: #0000BB">$id</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #0000BB">dba_fetch</span><span style="color: #007700">(</span><span style="color: #DD0000">"key"</span><span style="color: #007700">, </span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">dba_delete</span><span style="color: #007700">(</span><span style="color: #DD0000">"key"</span><span style="color: #007700">, </span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">dba_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> <p class="para"> DBA is binary safe and does not have any arbitrary limits. However, it inherits all limits set by the underlying database implementation. </p> <p class="para"> All file-based databases must provide a way of setting the file mode of a new created database, if that is possible at all. The file mode is commonly passed as the fourth argument to <a href="function.dba-open.html" class="function">dba_open()</a> or <a href="function.dba-popen.html" class="function">dba_popen()</a>. </p> <p class="para"> You can access all entries of a database in a linear way by using the <a href="function.dba-firstkey.html" class="function">dba_firstkey()</a> and <a href="function.dba-nextkey.html" class="function">dba_nextkey()</a> functions. You may not change the database while traversing it. </p> <p class="para"> <div class="example"> <p><b>Example #2 Traversing a database</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /><br /></span><span style="color: #FF8000">// ...open database...<br /><br /></span><span style="color: #0000BB">$key </span><span style="color: #007700">= </span><span style="color: #0000BB">dba_firstkey</span><span style="color: #007700">(</span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br /><br />while (</span><span style="color: #0000BB">$key </span><span style="color: #007700">!= </span><span style="color: #0000BB">false</span><span style="color: #007700">) {<br /> if (</span><span style="color: #0000BB">true</span><span style="color: #007700">) { </span><span style="color: #FF8000">// remember the key to perform some action later<br /> </span><span style="color: #0000BB">$handle_later</span><span style="color: #007700">[] = </span><span style="color: #0000BB">$key</span><span style="color: #007700">;<br /> }<br /> </span><span style="color: #0000BB">$key </span><span style="color: #007700">= </span><span style="color: #0000BB">dba_nextkey</span><span style="color: #007700">(</span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br />}<br /><br />foreach (</span><span style="color: #0000BB">$handle_later </span><span style="color: #007700">as </span><span style="color: #0000BB">$val</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">dba_delete</span><span style="color: #007700">(</span><span style="color: #0000BB">$val</span><span style="color: #007700">, </span><span style="color: #0000BB">$id</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="dba.constants.html">Predefined Constants</a></div> <div class="next" style="text-align: right; float: right;"><a href="ref.dba.html">DBA Functions</a></div> <div class="up"><a href="book.dba.html">DBA</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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