archived-doc-zh/reference/pgsql/functions/pg-fetch-object.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.pg-fetch-object" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>pg_fetch_object</refname>
  <refpurpose>获取一行作为对象</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>object</type><type>false</type></type><methodname>pg_fetch_object</methodname>
   <methodparam><type>PgSql\Result</type><parameter>result</parameter></methodparam>
   <methodparam choice="opt"><type class="union"><type>int</type><type>null</type></type><parameter>row</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>class</parameter><initializer>"stdClass"</initializer></methodparam>
   <methodparam choice="opt"><type>array</type><parameter>constructor_args</parameter><initializer>[]</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>pg_fetch_object</function> 返回对象，该对象的属性对应于获取的行的字段名称。它可以选择实例化特定类的对象，并将参数传递给该类的构造方法。
  </para>
  &database.fetch-null;
  <para>
   在速度方面，该函数与 <function>pg_fetch_array</function> 相同，并且几乎与 <function>pg_fetch_row</function> 一样快（差别不大）。
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>result</parameter></term>
     <listitem>
      &pgsql.parameter.result;
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>row</parameter></term>
     <listitem>
      <para>
       要获取的结果中的行号。行从 0 向上编号。如果省略或为 &null;，则获取下一行。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>class</parameter></term>
      <listitem>
       <para>
        要实例化、设置属性并返回的类的名称。如果未指定，则返回 <classname>stdClass</classname> 对象。
       </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>constructor_args</parameter></term>
      <listitem>
       <para>
        要传递给 <parameter>class</parameter> 对象的构造方法的可选参数 <type>array</type>。
       </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   结果中的每个字段名称都有在 <type>object</type> 中对应的属性。数据库 <literal>NULL</literal> 值作为 &null; 返回。
  </para>
  <para>
   如果 <parameter>row</parameter> 超过集合中的行数、没有更多行或任何其他错误，则返回 &false;。
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  <para>
   当 <parameter>constructor_args</parameter> 非空而类没有构造方法时，会抛出 <classname>ValueError</classname>。
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.3.0</entry>
      <entry>
       当 <parameter>constructor_args</parameter> 非空而类没有构造方法时，现在会抛出 <classname>ValueError</classname>
       异常；之前抛出 <classname>Exception</classname>。
      </entry>
     </row>
     &pgsql.changelog.result-object;
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>pg_fetch_object</function> 示例</title>
    <programlisting role="php">
<![CDATA[
<?php 

$database = "store";

$db_conn = pg_connect("host=localhost port=5432 dbname=$database");
if (!$db_conn) {
  echo "Failed connecting to postgres database $database\n";
  exit;
}

$qu = pg_query($db_conn, "SELECT * FROM books ORDER BY author");


while ($data = pg_fetch_object($qu)) {
  echo $data->author . " (";
  echo $data->year . "): ";
  echo $data->title . "<br />";
}

pg_free_result($qu);
pg_close($db_conn);

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

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>pg_query</function></member>
    <member><function>pg_fetch_array</function></member>
    <member><function>pg_fetch_assoc</function></member>
    <member><function>pg_fetch_row</function></member>
    <member><function>pg_fetch_result</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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