mysql-fetch-assoc.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.mysql-fetch-assoc" xmlns="http://docbook.org/ns/docbook">
   <refnamediv>
    <refname>mysql_fetch_assoc</refname>
    <refpurpose>
     从结果集中取得一行作为关联数组
    </refpurpose>
   </refnamediv>
 
 <refsynopsisdiv>
  <warning>
   &mysql.alternative.note;
   <simplelist role="alternatives">
    <member><function>mysqli_fetch_assoc</function></member>
    <member>
     <methodname>PDOStatement::fetch</methodname>
     with <parameter>mode</parameter> as <constant>PDO::FETCH_ASSOC</constant>
    </member>
   </simplelist>
  </warning>
 </refsynopsisdiv>
 
 <refsect1 role="description">
  &reftitle.description;
     <methodsynopsis>
      <type>array</type><methodname>mysql_fetch_assoc</methodname>
      <methodparam><type>resource</type><parameter>result</parameter></methodparam>
     </methodsynopsis>
    <para>
     返回对应结果集的关联数组，并且继续移动内部数据指针。
     <function>mysql_fetch_assoc</function> 和用
     <function>mysql_fetch_array</function> 加上第二个可选参数 
     MYSQL_ASSOC 完全相同。它仅仅返回关联数组。
    </para>
   </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    &mysql.result.description;
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
    返回根据从结果集取得的行生成的关联数组；如果没有更多行则返回 &false;。
  </para>
  <para>
   如果结果中的两个或以上的列具有相同字段名，最后一列将优先。要访问同名的其它列，要么用
     <function>mysql_fetch_row</function>
     来取得数字索引或给该列起个别名。
     参见
     <function>mysql_fetch_array</function> 例子中有关别名说明。
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>扩展的 <function>mysql_fetch_assoc</function> 例子</title>
    <programlisting role="php">
<![CDATA[
<?php

$conn = mysql_connect("localhost", "mysql_user", "mysql_password");

if (!$conn) {
    echo "Unable to connect to DB: " . mysql_error();
    exit;
}
  
if (!mysql_select_db("mydbname")) {
    echo "Unable to select mydbname: " . mysql_error();
    exit;
}

$sql = "SELECT id as userid, fullname, userstatus 
        FROM   sometable
        WHERE  userstatus = 1";

$result = mysql_query($sql);

if (!$result) {
    echo "Could not successfully run query ($sql) from DB: " . mysql_error();
    exit;
}

if (mysql_num_rows($result) == 0) {
    echo "No rows found, nothing to print so am exiting";
    exit;
}

// While a row of data exists, put that row in $row as an associative array
// Note: If you're expecting just one row, no need to use a loop
// Note: If you put extract($row); inside the following loop, you'll
//       then create $userid, $fullname, and $userstatus
while ($row = mysql_fetch_assoc($result)) {
    echo $row["userid"];
    echo $row["fullname"];
    echo $row["userstatus"];
}

mysql_free_result($result);

?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <title>性能</title>
   <para>
    必须指出一个要点：
     <function>mysql_fetch_assoc</function> 比
     <function>mysql_fetch_row</function>
     并<emphasis>不明显</emphasis> 
     慢，而且还提供了更多有用的值。
   </para>
  </note>
  &database.field-case;
  &database.fetch-null;
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>mysql_fetch_row</function></member>
    <member><function>mysql_fetch_array</function></member>
    <member><function>mysql_data_seek</function></member>
    <member><function>mysql_query</function></member>
    <member><function>mysql_error</function></member>
   </simplelist>
  </para>
 </refsect1>
  </refentry>

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