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50 lines
2.9 KiB
HTML
50 lines
2.9 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>向 MySQL 发送一条 SQL 查询，并不获取和缓存结果的行</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-unbuffered-query" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">mysql_unbuffered_query</h1>
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<p class="verinfo">(PHP 4 >= 4.0.6, PHP 5)</p><p class="refpurpose"><span class="refname">mysql_unbuffered_query</span> — <span class="dc-title">
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向 MySQL 发送一条 SQL 查询，并不获取和缓存结果的行
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</span></p>
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</div>
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<div class="refsect1 unknown-unknown-unknown-unknown-seealss" id="refsect1-function.mysql-unbuffered-query-unknown-unknown-unknown-unknown-seealss">
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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_unbuffered_query</strong></span>
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( <span class="methodparam"><span class="type">string</span> <code class="parameter">$query</code></span>
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[, <span class="methodparam"><span class="type">resource</span> <code class="parameter">$link_identifier</code></span>
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] ) : <span class="type">resource</span></div>
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<p class="para rdfs-comment">
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<span class="function"><strong>mysql_unbuffered_query()</strong></span> 向
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MySQL 发送一条 SQL 查询
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<code class="parameter">query</code>，但不像
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<span class="function"><a href="mysql_query.html" class="function">mysql_query()</a></span>
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那样自动获取并缓存结果集。一方面，这在处理很大的结果集时会节省可观的内存。另一方面，可以在获取第一行后立即对结果集进行操作，而不用等到整个
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SQL 语句都执行完毕。当使用多个数据库连接时，必须指定可选参数
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<code class="parameter">link_identifier</code>。
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</p>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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<span class="function"><strong>mysql_unbuffered_query()</strong></span>
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的好处是有代价的：在
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<span class="function"><strong>mysql_unbuffered_query()</strong></span>
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返回的结果集之上不能使用
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<span class="function"><a href="mysql_num_rows.html" class="function">mysql_num_rows()</a></span> 和 <span class="function"><a href="mysql_data_seek.html" class="function">mysql_data_seek()</a></span>。此外在向
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MySQL 发送一条新的 SQL
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查询之前，必须提取掉所有未缓存的 SQL
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查询所产生的结果行。
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</p>
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</p></blockquote>
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<p class="para">
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参见 <span class="function"><a href="mysql_query.html" class="function">mysql_query()</a></span>。
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</p>
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</div>
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</div></div></div></body></html> |