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168 lines
11 KiB
HTML
<!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>取得前一次 MySQL 操作所影响的记录行数</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-affected-rows" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">mysql_affected_rows</h1>
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<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">mysql_affected_rows</span> — <span class="dc-title">取得前一次 MySQL 操作所影响的记录行数</span></p>
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</div>
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<div id="function.mysql-affected-rows-refsynopsisdiv">
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<div class="warning"><strong class="warning">Warning</strong>
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<p class="para">本扩展自 PHP 5.5.0
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起已废弃，并在自 PHP 7.0.0 开始被移除。应使用 <a href="book.mysqli.html" class="link">MySQLi</a>
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或 <a href="ref.pdo_mysql.html" class="link">PDO_MySQL</a> 扩展来替换之。参见
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<a href="mysqlinfo.api.choosing.html" class="link">MySQL：选择 API</a> 指南以及<a href="faq.databases.html#faq.databases.mysql.deprecated" class="link">相关 FAQ</a> 来获取更多信息。用以替代本函数的有：</p>
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="mysqli.affected_rows.html" class="function">mysqli_affected_rows()</a></span></li>
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<li class="member"><span class="methodname"><a href="pdostatement.rowcount.html" class="methodname">PDOStatement::rowCount()</a></span></li>
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</ul>
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</div>
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</div>
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<div class="refsect1 description" id="refsect1-function.mysql-affected-rows-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_affected_rows</strong></span>
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([ <span class="methodparam"><span class="type">resource</span> <code class="parameter">$link_identifier</code><span class="initializer"> = NULL</span></span>
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] ) : <span class="type">int</span></div>
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<p class="para rdfs-comment">
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取得最近一次与 <code class="parameter">link_identifier</code> 关联的
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INSERT，UPDATE 或 DELETE 查询所影响的记录行数。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.mysql-affected-rows-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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link_identifier</code></dt>
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<dd>
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<p class="para">MySQL
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连接。如不指定连接标识，则使用由 <span class="function"><a href="mysql_connect.html" class="function">mysql_connect()</a></span>
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最近打开的连接。如果没有找到该连接，会尝试不带参数调用
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<span class="function"><a href="mysql_connect.html" class="function">mysql_connect()</a></span>
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来创建。如没有找到连接或无法建立连接，则会生成
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<strong><code>E_WARNING</code></strong> 级别的错误。</p></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-affected-rows-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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执行成功则返回受影响的行的数目，如果最近一次查询失败的话，函数返回 -1。
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</p>
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<p class="para">
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如果最近一次操作是没有任何条件（WHERE）的 DELETE
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查询，在表中所有的记录都会被删除，但本函数返回值在 4.1.2 版之前都为 0。
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</p>
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<p class="para">
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当使用 UPDATE 查询，MySQL 不会将原值和新值一样的列更新。这样使得
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<span class="function"><strong>mysql_affected_rows()</strong></span>
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函数返回值不一定就是查询条件所符合的记录数，只有真正被修改的记录数才会被返回。
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</p>
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<p class="para">
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REPLACE 语句首先删除具有相同主键的记录，然后插入一个新记录。本函数返回的是被删除的记录数加上被插入的记录数。
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</p>
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<p class="para">
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"INSERT ... ON DUPLICATE KEY UPDATE" 这种情况的查询，当执行了一次 INSERT 返回的值会是 <em>1</em>；如果是对已经存在的记录执行一次 UPDATE 将返回 <em>2</em>。
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.mysql-affected-rows-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-2116">
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<p><strong>Example #1 <span class="function"><strong>mysql_affected_rows()</strong></span> 例子</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 />$link </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">$link</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">'mydb'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* 本例返回被删除记录的准确数目 */<br /></span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">'DELETE FROM mytable WHERE id < 10'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Records deleted: %d\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">mysql_affected_rows</span><span style="color: #007700">());<br /><br /></span><span style="color: #FF8000">/* 对于非真值的 WHERE 子句，应返回 0 */<br /></span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">'DELETE FROM mytable WHERE 0'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Records deleted: %d\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">mysql_affected_rows</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 class="example-contents"><p>以上例程的输出类似于：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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Records deleted: 10
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Records deleted: 0
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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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<div class="example" id="example-2117">
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<p><strong>Example #2 使用事务处理的 <span class="function"><strong>mysql_affected_rows()</strong></span> 例子</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 />$link </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">$link</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">'mydb'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* Update records */<br /></span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"UPDATE mytable SET used=1 WHERE id < 10"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">printf </span><span style="color: #007700">(</span><span style="color: #DD0000">"Updated records: %d\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">mysql_affected_rows</span><span style="color: #007700">());<br /></span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"COMMIT"</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 class="example-contents"><p>以上例程的输出类似于：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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Updated Records: 10
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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-affected-rows-notes">
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<h3 class="title">注释</h3>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<strong>事务处理</strong><br />
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<p class="para">
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如果使用事务处理（transactions），需要在 INSERT，UPDATE 或 DELETE 查询后调用
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<span class="function"><strong>mysql_affected_rows()</strong></span> 函数，而不是在 COMMIT 命令之后。
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</p>
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</p></blockquote>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<strong>SELECT 语句</strong><br />
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<p class="para">
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要获取 SELECT 所返回的行数，可以用
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<span class="function"><a href="mysql_num_rows.html" class="function">mysql_num_rows()</a></span>。
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</p>
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</p></blockquote>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<strong>Cascaded 外键</strong><br />
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<p class="para">
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<span class="function"><strong>mysql_affected_rows()</strong></span> does not count rows affected
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implicitly through the use of ON DELETE CASCADE and/or ON UPDATE CASCADE
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in foreign key constraints.
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</p>
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</p></blockquote>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.mysql-affected-rows-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_num_rows.html" class="function" rel="rdfs-seeAlso">mysql_num_rows()</a> - 取得结果集中行的数目</span></li>
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<li class="member"><span class="function"><a href="mysql_info.html" class="function" rel="rdfs-seeAlso">mysql_info()</a> - 取得最近一条查询的信息</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> |