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254 lines
19 KiB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>从结果集中取得列信息并作为对象返回</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.mysql-fetch-field" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">mysql_fetch_field</h1>
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<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">mysql_fetch_field</span> — <span class="dc-title">
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从结果集中取得列信息并作为对象返回
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</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.mysql-fetch-field-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>mysql_fetch_field</strong></span>
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( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$result</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$field_offset</code></span>
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] ) : <span class="type">object</span></div>
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<p class="para rdfs-comment">
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返回一个包含字段信息的对象。
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</p>
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<p class="para">
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<span class="function"><strong>mysql_fetch_field()</strong></span>
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可以用来从某个查询结果中取得字段的信息。如果没有指定字段偏移量，则下一个尚未被
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<span class="function"><strong>mysql_fetch_field()</strong></span> 取得的字段被提取。
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</p>
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<p class="para">
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对象的属性为：
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<ul class="itemizedlist">
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<li class="listitem">
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<span class="simpara">
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name - 列名
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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table - 该列所在的表名
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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max_length - 该列最大长度
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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not_null - 1，如果该列不能为 <strong><code>NULL</code></strong>
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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primary_key - 1，如果该列是 primary key
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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unique_key - 1，如果该列是 unique key
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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multiple_key - 1，如果该列是 non-unique key
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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numeric - 1，如果该列是 numeric
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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blob - 1，如果该列是 BLOB
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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type - 该列的类型
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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unsigned - 1，如果该列是无符号数
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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zerofill - 1，如果该列是 zero-filled
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</span>
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</li>
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</ul>
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</p>
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<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数返回的字段名<em class="emphasis">大小写敏感</em>。</span></p></blockquote>
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<p class="para">
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<div class="example" id="example-2139">
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<p><strong>Example #1 <span class="function"><strong>mysql_fetch_field()</strong></span></strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br />mysql_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'localhost:3306'</span><span style="color: #007700">, </span><span style="color: #0000BB">$user</span><span style="color: #007700">, </span><span style="color: #0000BB">$password</span><span style="color: #007700">)<br /> or die(</span><span style="color: #DD0000">"Could not connect: " </span><span style="color: #007700">. </span><span style="color: #0000BB">mysql_error</span><span style="color: #007700">());<br /></span><span style="color: #0000BB">mysql_select_db</span><span style="color: #007700">(</span><span style="color: #DD0000">"database"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"select * from table"</span><span style="color: #007700">)<br /> or die(</span><span style="color: #DD0000">"Query failed: " </span><span style="color: #007700">. </span><span style="color: #0000BB">mysql_error</span><span style="color: #007700">());<br /></span><span style="color: #FF8000">/* get column metadata */<br /></span><span style="color: #0000BB">$i </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">;<br />while (</span><span style="color: #0000BB">$i </span><span style="color: #007700">< </span><span style="color: #0000BB">mysql_num_fields</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"Information for column </span><span style="color: #0000BB">$i</span><span style="color: #DD0000">:<br />\n"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$meta </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_fetch_field</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br /> if (!</span><span style="color: #0000BB">$meta</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"No information available<br />\n"</span><span style="color: #007700">;<br /> }<br /> echo </span><span style="color: #DD0000">"<pre><br />blob: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">blob</span><span style="color: #DD0000"><br />max_length: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">max_length</span><span style="color: #DD0000"><br />multiple_key: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">multiple_key</span><span style="color: #DD0000"><br />name: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">name</span><span style="color: #DD0000"><br />not_null: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">not_null</span><span style="color: #DD0000"><br />numeric: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">numeric</span><span style="color: #DD0000"><br />primary_key: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">primary_key</span><span style="color: #DD0000"><br />table: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">table</span><span style="color: #DD0000"><br />type: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">type</span><span style="color: #DD0000"><br />unique_key: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">unique_key</span><span style="color: #DD0000"><br />unsigned: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">unsigned</span><span style="color: #DD0000"><br />zerofill: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">zerofill</span><span style="color: #DD0000"><br /></pre>"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$i</span><span style="color: #007700">++;<br />}<br /></span><span style="color: #0000BB">mysql_free_result</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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<p class="para">
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参见 <span class="function"><a href="mysql_field_seek.html" class="function">mysql_field_seek()</a></span>。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.mysql-fetch-field-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">
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result</code></dt>
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<dd>
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<p class="para"><span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span>
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型的结果集。此结果集来自对 <span class="function"><a href="mysql_query.html" class="function">mysql_query()</a></span>
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的调用。</p></dd>
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<dt>
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<code class="parameter">field_offset</code></dt>
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<dd>
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<p class="para">
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The numerical field offset. If the field offset is not specified, the
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next field that was not yet retrieved by this function is retrieved.
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The <code class="parameter">field_offset</code> starts at <em>0</em>.
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.mysql-fetch-field-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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Returns an <span class="type"><a href="language.types.object.html" class="type object">object</a></span> containing field information. The properties
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of the object are:
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</p>
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<p class="para">
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<ul class="itemizedlist">
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<li class="listitem">
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<span class="simpara">
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name - column name
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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table - name of the table the column belongs to
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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max_length - maximum length of the column
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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not_null - 1 if the column cannot be <strong><code>NULL</code></strong>
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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primary_key - 1 if the column is a primary key
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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unique_key - 1 if the column is a unique key
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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multiple_key - 1 if the column is a non-unique key
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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numeric - 1 if the column is numeric
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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blob - 1 if the column is a BLOB
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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type - the type of the column
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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unsigned - 1 if the column is unsigned
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</span>
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</li>
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<li class="listitem">
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<span class="simpara">
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zerofill - 1 if the column is zero-filled
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</span>
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</li>
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</ul>
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.mysql-fetch-field-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-2140">
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<p><strong>Example #2 <span class="function"><strong>mysql_fetch_field()</strong></span> example</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br />$conn </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'localhost'</span><span style="color: #007700">, </span><span style="color: #DD0000">'mysql_user'</span><span style="color: #007700">, </span><span style="color: #DD0000">'mysql_password'</span><span style="color: #007700">);<br />if (!</span><span style="color: #0000BB">$conn</span><span style="color: #007700">) {<br /> die(</span><span style="color: #DD0000">'Could not connect: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">mysql_error</span><span style="color: #007700">());<br />}<br /></span><span style="color: #0000BB">mysql_select_db</span><span style="color: #007700">(</span><span style="color: #DD0000">'database'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">'select * from table'</span><span style="color: #007700">);<br />if (!</span><span style="color: #0000BB">$result</span><span style="color: #007700">) {<br /> die(</span><span style="color: #DD0000">'Query failed: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">mysql_error</span><span style="color: #007700">());<br />}<br /></span><span style="color: #FF8000">/* get column metadata */<br /></span><span style="color: #0000BB">$i </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">;<br />while (</span><span style="color: #0000BB">$i </span><span style="color: #007700">< </span><span style="color: #0000BB">mysql_num_fields</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"Information for column </span><span style="color: #0000BB">$i</span><span style="color: #DD0000">:<br />\n"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$meta </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_fetch_field</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">, </span><span style="color: #0000BB">$i</span><span style="color: #007700">);<br /> if (!</span><span style="color: #0000BB">$meta</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"No information available<br />\n"</span><span style="color: #007700">;<br /> }<br /> echo </span><span style="color: #DD0000">"<pre><br />blob: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">blob</span><span style="color: #DD0000"><br />max_length: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">max_length</span><span style="color: #DD0000"><br />multiple_key: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">multiple_key</span><span style="color: #DD0000"><br />name: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">name</span><span style="color: #DD0000"><br />not_null: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">not_null</span><span style="color: #DD0000"><br />numeric: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">numeric</span><span style="color: #DD0000"><br />primary_key: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">primary_key</span><span style="color: #DD0000"><br />table: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">table</span><span style="color: #DD0000"><br />type: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">type</span><span style="color: #DD0000"><br />unique_key: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">unique_key</span><span style="color: #DD0000"><br />unsigned: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">unsigned</span><span style="color: #DD0000"><br />zerofill: </span><span style="color: #0000BB">$meta</span><span style="color: #007700">-></span><span style="color: #0000BB">zerofill</span><span style="color: #DD0000"><br /></pre>"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$i</span><span style="color: #007700">++;<br />}<br /></span><span style="color: #0000BB">mysql_free_result</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 notes" id="refsect1-function.mysql-fetch-field-notes">
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<h3 class="title">注释</h3>
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<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数返回的字段名<em class="emphasis">大小写敏感</em>。</span></p></blockquote>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.mysql-fetch-field-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="mysql_field_seek.html" class="function" rel="rdfs-seeAlso">mysql_field_seek()</a> - 将结果集中的指针设定为制定的字段偏移量</span></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |