pdo.prepare.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>Prepares a statement for execution and returns a statement object</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="pdo.lastinsertid.html">PDO::lastInsertId</a></div> <div class="next" style="text-align: right; float: right;"><a href="pdo.query.html">PDO::query</a></div> <div class="up"><a href="class.pdo.html">PDO</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="pdo.prepare" class="refentry"> <div class="refnamediv"> <h1 class="refname">PDO::prepare</h1> <p class="verinfo">(PHP 5 >= 5.1.0, PECL pdo:0.1-1.0.3)</p><p class="refpurpose"><span class="refname">PDO::prepare</span> — <span class="dc-title"> Prepares a statement for execution and returns a statement object </span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type"><a href="class.pdostatement.html" class="type PDOStatement">PDOStatement</a></span> <span class="methodname"><b><b>PDO::prepare</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$statement</tt></span> [, <span class="methodparam"><span class="type">array</span> <tt class="parameter">$driver_options</tt></span> ] )</div> <p class="para rdfs-comment"> Prepares an SQL statement to be executed by the <a href="pdostatement.execute.html" class="function">PDOStatement::execute()</a> method. The SQL statement can contain zero or more named (:name) or question mark (?) parameter markers for which real values will be substituted when the statement is executed. You cannot use both named and question mark parameter markers within the same SQL statement; pick one or the other parameter style. </p> <p class="para"> You must include a unique parameter marker for each value you wish to pass in to the statement when you call <a href="pdostatement.execute.html" class="function">PDOStatement::execute()</a>. You cannot use a named parameter marker of the same name twice in a prepared statement. You cannot bind multiple values to a single named parameter in, for example, the IN() clause of an SQL statement. </p> <p class="para"> Calling <b>PDO::prepare()</b> and <a href="pdostatement.execute.html" class="function">PDOStatement::execute()</a> for statements that will be issued multiple times with different parameter values optimizes the performance of your application by allowing the driver to negotiate client and/or server side caching of the query plan and meta information, and helps to prevent SQL injection attacks by eliminating the need to manually quote the parameters. </p> <p class="para"> PDO will emulate prepared statements/bound parameters for drivers that do not natively support them, and can also rewrite named or question mark style parameter markers to something more appropriate, if the driver supports one style but not the other. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">statement</tt></i></span> <dd> <p class="para"> This must be a valid SQL statement for the target database server. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">driver_options</tt></i></span> <dd> <p class="para"> This array holds one or more key=>value pairs to set attribute values for the PDOStatement object that this method returns. You would most commonly use this to set the <i>PDO::ATTR_CURSOR</i> value to <i>PDO::CURSOR_SCROLL</i> to request a scrollable cursor. Some drivers have driver specific options that may be set at prepare-time. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> If the database server successfully prepares the statement, <b>PDO::prepare()</b> returns a PDOStatement object. If the database server cannot successfully prepare the statement, <b>PDO::prepare()</b> returns <b><tt>FALSE</tt></b>. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"><p><b>Example #1 Prepare an SQL statement with named parameters</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/* Execute a prepared statement by passing an array of values */<br /></span><span style="color: #0000BB">$sql </span><span style="color: #007700">= </span><span style="color: #DD0000">'SELECT name, colour, calories<br /> FROM fruit<br /> WHERE calories < :calories AND colour = :colour'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$sth </span><span style="color: #007700">= </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-></span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #0000BB">$sql</span><span style="color: #007700">, array(</span><span style="color: #0000BB">PDO</span><span style="color: #007700">::</span><span style="color: #0000BB">ATTR_CURSOR </span><span style="color: #007700">=> </span><span style="color: #0000BB">PDO</span><span style="color: #007700">::</span><span style="color: #0000BB">CURSOR_FWDONLY</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(array(</span><span style="color: #DD0000">':calories' </span><span style="color: #007700">=> </span><span style="color: #0000BB">150</span><span style="color: #007700">, </span><span style="color: #DD0000">':colour' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'red'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$red </span><span style="color: #007700">= </span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">fetchAll</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'calories' </span><span style="color: #007700">=> </span><span style="color: #0000BB">175</span><span style="color: #007700">, </span><span style="color: #DD0000">'colour' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'yellow'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$yellow </span><span style="color: #007700">= </span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">fetchAll</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> <div class="example"> <p><b>Example #2 Prepare an SQL statement with question mark parameters</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/* Execute a prepared statement by passing an array of values */<br /></span><span style="color: #0000BB">$sth </span><span style="color: #007700">= </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-></span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #DD0000">'SELECT name, colour, calories<br /> FROM fruit<br /> WHERE calories < ? AND colour = ?'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(array(</span><span style="color: #0000BB">150</span><span style="color: #007700">, </span><span style="color: #DD0000">'red'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$red </span><span style="color: #007700">= </span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">fetchAll</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(array(</span><span style="color: #0000BB">175</span><span style="color: #007700">, </span><span style="color: #DD0000">'yellow'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">$yellow </span><span style="color: #007700">= </span><span style="color: #0000BB">$sth</span><span style="color: #007700">-></span><span style="color: #0000BB">fetchAll</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="pdo.exec.html" class="function" rel="rdfs-seeAlso">PDO::exec()</a></li> <li class="member"><a href="pdo.query.html" class="function" rel="rdfs-seeAlso">PDO::query()</a></li> <li class="member"><a href="pdostatement.execute.html" class="function" rel="rdfs-seeAlso">PDOStatement::execute()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="pdo.lastinsertid.html">PDO::lastInsertId</a></div> <div class="next" style="text-align: right; float: right;"><a href="pdo.query.html">PDO::query</a></div> <div class="up"><a href="class.pdo.html">PDO</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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