PDO::prepare
(PHP 5 >= 5.1.0, PECL pdo:0.1-1.0.3)
PDO::prepare —
Prepares a statement for execution and returns a statement object
Description
PDOStatement PDO::prepare
(
string $statement
[,
array $driver_options
] )
You must include a unique parameter marker for each value you wish to pass
in to the statement when you call PDOStatement::execute().
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.
Calling PDO::prepare() and
PDOStatement::execute() 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.
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.
Parameters
-
statement
-
This must be a valid SQL statement for the target database server.
-
driver_options
-
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
PDO::ATTR_CURSOR value to
PDO::CURSOR_SCROLL to request a scrollable cursor.
Some drivers have driver specific options that may be set at
prepare-time.
Return Values
If the database server successfully prepares the statement,
PDO::prepare() returns a PDOStatement object.
If the database server cannot successfully prepare the statement,
PDO::prepare() returns FALSE.
Examples
Example #1 Prepare an SQL statement with named parameters
<?php
/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
FROM fruit
WHERE calories < :calories AND colour = :colour';
$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));
$red = $sth->fetchAll();
$sth->execute(array('calories' => 175, 'colour' => 'yellow'));
$yellow = $sth->fetchAll();
?>
Example #2 Prepare an SQL statement with question mark parameters
<?php
/* Execute a prepared statement by passing an array of values */
$sth = $dbh->prepare('SELECT name, colour, calories
FROM fruit
WHERE calories < ? AND colour = ?');
$sth->execute(array(150, 'red'));
$red = $sth->fetchAll();
$sth->execute(array(175, 'yellow'));
$yellow = $sth->fetchAll();
?>
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