archived-doc-zh/reference/pgsql/functions/pg-connect.xml

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<refentry xml:id="function.pg-connect" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>pg_connect</refname>
  <refpurpose>打开 PostgreSQL 连接</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>PgSql\Connection</type><type>false</type></type><methodname>pg_connect</methodname>
   <methodparam><type>string</type><parameter>connection_string</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>flags</parameter><initializer>0</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>pg_connect</function> 打开通过 <parameter>connection_string</parameter> 指定的 PostgreSQL 数据库的连接。
  </para>
  <para>
   如果使用与现有连接相同的 <parameter>connection_string</parameter> 对 <function>pg_connect</function>
   进行第二次调用，将返回现有连接，除非将 <constant>PGSQL_CONNECT_FORCE_NEW</constant> 作为
   <parameter>flags</parameter> 传递。
  </para>
  <para>
   弃用有多个参数的旧语法 <command>$conn = pg_connect("host", "port", "options", "tty", "dbname")</command>。
  </para>
 </refsect1>

<refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>connection_string</parameter></term>
     <listitem>
      <para>
       <parameter>connection_string</parameter> 可以为空以使用所有默认参数，或者可以包含一个或多个由空格分隔的参数设置。
       每个参数设置的形式为 <literal>keyword = value</literal>。等号两旁的空格是可选的。写入空值或包含空格的值，请用单引号将其括起来，例如
       <literal>keyword = 'a value'</literal>。值中的单引号和反斜线必须使用反斜线转义，即 \' 和 \\。
      </para>
      <para>
       当前可识别的参数关键字有
       <parameter>host</parameter>、<parameter>hostaddr</parameter>、<parameter>port</parameter>、<parameter>dbname</parameter>（默认为
       <parameter>user</parameter> 的值）、<parameter>user</parameter>、<parameter>password</parameter>、<parameter>connect_timeout</parameter>、<parameter>options</parameter>、<parameter>tty</parameter>（忽略）、<parameter>sslmode</parameter>、<parameter>requiressl</parameter>（弃用
       <parameter>sslmode</parameter>）和 <parameter>service</parameter>。存在哪些参数取决于 PostgreSQL 版本。
      </para>
      <para>
       The <parameter>options</parameter> parameter can be used to set command line parameters 
       to be invoked by the server.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>flags</parameter></term>
     <listitem>
      <para>
       如果传递 <constant>PGSQL_CONNECT_FORCE_NEW</constant>，将会创建新连接，即使 <parameter>connection_string</parameter>
       与现有连接相同。
      </para>
      <para>
       如果指定 <constant>PGSQL_CONNECT_ASYNC</constant>，然后连接是异步创建。连接状态可以通过
       <function>pg_connect_poll</function> 或 <function>pg_connection_status</function> 检测。
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   成功时返回 <classname>PgSql\Connection</classname> 实例，&return.falseforfailure;。
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.1.0</entry>
      <entry>
       现在返回 <classname>PgSql\Connection</classname> 实例；之前返回 &resource;。
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>使用 <function>pg_connect</function></title>
    <programlisting role="php">
<![CDATA[
<?php
$dbconn = pg_connect("dbname=mary");
//connect to a database named "mary"

$dbconn2 = pg_connect("host=localhost port=5432 dbname=mary");
// connect to a database named "mary" on "localhost" at port "5432"

$dbconn3 = pg_connect("host=sheep port=5432 dbname=mary user=lamb password=foo");
//connect to a database named "mary" on the host "sheep" with a username and password

$conn_string = "host=sheep port=5432 dbname=test user=lamb password=bar";
$dbconn4 = pg_connect($conn_string);
//connect to a database named "test" on the host "sheep" with a username and password

$dbconn5 = pg_connect("host=localhost options='--client_encoding=UTF8'");
//connect to a database on "localhost" and set the command line parameter which tells the encoding is in UTF-8
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>pg_pconnect</function></member>
    <member><function>pg_close</function></member>
    <member><function>pg_host</function></member>
    <member><function>pg_port</function></member>
    <member><function>pg_tty</function></member>
    <member><function>pg_options</function></member>
    <member><function>pg_dbname</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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