Detailed explanation of mysql PDO::prepare usage

PDO::prepare — Prepare the SQL statement to be executed and return a PDOStatement object (PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)

Description

Syntax

public PDOStatement PDO::prepare ( string $statement [, array $driver_options = array() ] )

Prepare the SQL statement to be executed for the PDOStatement::execute() method. The SQL statement can contain zero or more named (:name) or question mark (?) parameters. Mark, parameters will be replaced when SQL is executed.

You cannot include both named (:name) or question mark (?) parameter markers in the SQL statement. You can only choose one of the styles.

The parameters in the preprocessed SQL statement will pass the real parameters when using the PDOStatement::execute() method.

Parameters

statement: Legal SQL statement.

driver_options: This array contains one or more key=>value pairs to set the properties of the PDOStatement object. The most commonly used is to set the PDO::ATTR_CURSOR value to PDO::CURSOR_SCROLL to request a scrollable cursor.

Return value

If successful, PDO::prepare() returns a PDOStatement object. If it fails, it returns FALSE or throws an exception PDOException.

Example

Use named (:name) parameters to prepare SQL statements

<?php
/* 通过数组值向预处理语句传递值 */
$sql = &#39;SELECT name, colour, calories
    FROM fruit
    WHERE calories < :calories AND colour = :colour&#39;;
    $sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
    $sth->execute(array(&#39;:calories&#39; => 150, &#39;:colour&#39; => &#39;red&#39;));
    $red = $sth->fetchAll();
    $sth->execute(array(&#39;:calories&#39; => 175, &#39;:colour&#39; => &#39;yellow&#39;));
    $yellow = $sth->fetchAll();
    ?>

Use question mark (?) parameters to prepare SQL statements

<?php
/* 通过数组值向预处理语句传递值 */
$sth = $dbh->prepare(&#39;SELECT name, colour, calories
    FROM fruit
    WHERE calories < ? AND colour = ?&#39;);$sth->execute(array(150, &#39;red&#39;));
    $red = $sth->fetchAll();
    $sth->execute(array(175, &#39;yellow&#39;));
    $yellow = $sth->fetchAll();
    ?>

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