Introduction - Query
Introduction - Query – Performing queries
Описание
PEAR DB provides several methods for querying databases. The most direct method is query(). It takes a SQL query string as an argument. There are three possible returns: a new DB_result object for queries that return results (such as SELECT queries), DB_OK for queries that manipulate data (such as INSERT queries) or a DB_Error object on failure.
Doing a query
<?php
// Create a valid DB object named $db
// at the beginning of your program...
require_once 'DB.php';
$db =& DB::connect('pgsql://usr:pw@localhost/dbnam');
if (PEAR::isError($db)) {
die($db->getMessage());
}
// Proceed with a query...
$res =& $db->query('SELECT * FROM clients');
// Always check that result is not an error
if (PEAR::isError($res)) {
die($res->getMessage());
}
?>
query() can be used instead of
prepare() and
execute(), if you
set the $params parameter
and your query uses placeholders.
Using query in prepare/execute mode with a scalar parameter
<?php
// Once you have a valid DB object named $db...
$sql = 'select * from clients where clientid = ?';
$data = 53;
$res =& $db->query($sql, $data);
// Always check that result is not an error
if (PEAR::isError($res)) {
die($res->getMessage());
}
?>
Using query in prepare/execute mode with an array parameter
<?php
// Once you have a valid DB object named $db...
$sql = 'select * from clients where clientid = ? and statusid = ?';
$data = array(53, 4);
$res =& $db->query($sql, $data);
// Always check that result is not an error
if (PEAR::isError($res)) {
die($res->getMessage());
}
?>