This example unlinks a large object from the database prior to deleting
the row that references it from the blobs table we've been using in
our PDO::pgsqlLOBCreate() and
PDO::pgsqlLOBOpen() examples.
<?php
$db = new PDO('pgsql:dbname=test host=localhost', $user, $pass);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db->beginTransaction();
$db->pgsqlLOBUnlink($oid);
$stmt = $db->prepare("DELETE FROM BLOBS where ident = ?");
$stmt->execute(array($some_id));
$db->commit();
?>