Introduction - Query
Introduction - Query -- Performing queries
Description
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());
}
?>
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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());
}
?>
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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());
}
?>
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