mysqli.connect.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Open a new connection to the MySQL server</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="mysqli.connect-error.html">mysqli->connect_error</a></div> <div class="next" style="text-align: right; float: right;"><a href="mysqli.debug.html">mysqli::debug</a></div> <div class="up"><a href="class.mysqli.html">MySQLi</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="mysqli.connect" class="refentry"> <div class="refnamediv"> <h1 class="refname">mysqli::__construct</h1> <h1 class="refname">mysqli_connect</h1> <p class="verinfo">(PHP 5)</p><p class="refpurpose"><span class="refname">mysqli::__construct</span> -- <span class="refname">mysqli_connect</span> — <span class="dc-title">Open a new connection to the MySQL server</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <p class="para">Object oriented style (constructor):</p> <div class="constructorsynopsis dc-description"> <span class="methodname"><b><b>mysqli::__construct</b></b></span> ([ <span class="methodparam"><span class="type">string</span> <tt class="parameter">$host</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$username</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$passwd</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$dbname</tt></span> [, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$port</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$socket</tt></span> ]]]]]] )</div> <p class="para rdfs-comment">Procedural style</p> <div class="methodsynopsis dc-description"> <span class="type"><a href="class.mysqli.html" class="type mysqli">mysqli</a></span> <span class="methodname"><b><b>mysqli_connect</b></b></span> ([ <span class="methodparam"><span class="type">string</span> <tt class="parameter">$host</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$username</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$passwd</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$dbname</tt></span> [, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$port</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$socket</tt></span> ]]]]]] )</div> <p class="para rdfs-comment"> Opens a connection to the MySQL Server running on. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">host</tt></i></span> <dd> <p class="para"> Can be either a host name or an IP address. Passing the <b><tt>NULL</tt></b> value or the string "localhost" to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">username</tt></i></span> <dd> <p class="para"> The MySQL user name. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">passwd</tt></i></span> <dd> <p class="para"> If not provided or <b><tt>NULL</tt></b>, the MySQL server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password as provided or not). </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">dbname</tt></i></span> <dd> <p class="para"> If provided will specify the default database to be used when performing queries. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">port</tt></i></span> <dd> <p class="para"> Specifies the port number to attempt to connect to the MySQL server. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">socket</tt></i></span> <dd> <p class="para"> Specifies the socket or named pipe that should be used. </p> <blockquote><p><b class="note">Note</b>: Specifying the <i><tt class="parameter">socket</tt></i> parameter will not explicitly determine the type of connection to be used when connecting to the MySQL server. How the connection is made to the MySQL database is determined by the <i><tt class="parameter">host</tt></i> parameter. <br /> </p></blockquote> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns a object which represents the connection to a MySQL Server. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <div class="example"> <p><b>Example #1 Object oriented style</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* check connection */<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">connect_error</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Connect failed: %s\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">mysqli_connect_error</span><span style="color: #007700">());<br /> exit();<br />}<br /><br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Host information: %s\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">host_info</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* close connection */<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">close</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> <div class="example"> <p><b>Example #2 Procedural style</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$link </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* check connection */<br /></span><span style="color: #007700">if (!</span><span style="color: #0000BB">$link</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Connect failed: %s\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">mysqli_connect_error</span><span style="color: #007700">());<br /> exit();<br />}<br /><br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Host information: %s\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">mysqli_get_host_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">/* close connection */<br /></span><span style="color: #0000BB">mysqli_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> <p class="para">The above example will output:</p> <div class="example-contents"><pre><div class="cdata"><pre>Host information: Localhost via UNIX socket</pre></div> </pre></div> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <blockquote><p><b class="note">Note</b>: OO syntax only: If a connection fails an object is still returned. To check if the connection failed then use the <a href="mysqli.connect-error.html" class="link">mysqli->connect_error</a> property like in the examples above. <br /> </p></blockquote> <blockquote><p><b class="note">Note</b>: Error "Can't create TCP/IP socket (10106)" usually means that the <a href="ini.core.html#ini.variables-order" class="link">variables_order</a> configure directive doesn't contain character <i>E</i>. On Windows, if the environment is not copied the <i>SYSTEMROOT</i> environment variable won't be available and PHP will have problems loading Winsock. <br /> </p></blockquote> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="mysqli.connect-error.html">mysqli->connect_error</a></div> <div class="next" style="text-align: right; float: right;"><a href="mysqli.debug.html">mysqli::debug</a></div> <div class="up"><a href="class.mysqli.html">MySQLi</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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