Quick extension to PDO that Makes Life Easier(TM)

database.php

<?php
class DB extends PDO {
    function __construct($dsn, $user = NULL, $password = NULL) {
        $params = array(
            PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\'',
            PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,
            PDO::ATTR_PERSISTENT => TRUE,
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_ORACLE_NULLS => PDO::NULL_EMPTY_STRING,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC);
        parent::__construct($dsn, $user, $password, $params);
    }

    function replace($table, array $data) {
        return $this->insert($table, $data, TRUE);
    }

    function insert($table, array $data, $replace = FALSE) {
        $fields = array_keys($data);
        $values = array_fill(0, count($data), '?');

        $sql = sprintf("%s INTO %s (%s) VALUES (%s)",
                $replace ? 'REPLACE' : 'INSERT',
                $table, implode(',', $fields), implode(',', $values));
        $stmt = $this->prepare($sql);
        if( $stmt->execute(array_values($data)) ) {
            return $this->lastInsertId();
        }
        return FALSE;
    }

    function insert_or_update($table, array $data, array $id_fields) {
        // Build insert
        $params = array_values($data);
        $fields = array_keys($data);
        $values = array_fill(0, count($data), '?');
        $sql = sprintf("INSERT INTO %s (%s) VALUES (%s)",
                $table, implode(',', $fields), implode(',', $values));

        // Or update when duplicate key
        $set = array();
        foreach( $data AS $k => $v ) {
            if( in_array($k, $id_fields) ) continue;
            $set[] = sprintf("%s = ?", $k);
            $params[] = $v;
        }
        $sql .= ' ON DUPLICATE KEY UPDATE ' . implode(',', $set);
        $stmt = $this->prepare($sql);
        $stmt->execute($params);
        $id = $this->lastInsertId();
        return $id;
    }

    function update($table, array $where, array $data) {
        $set = array();
        $params = array();
        foreach( $data AS $k => $v ) {
            $set[] = sprintf("%s = ?", $k);
            $params[] = $v;
        }

        $db = Object('db');
        $sql = sprintf("UPDATE %s SET %s WHERE %s", $table, implode(',',$set), implode(' AND ', $where));
        $stmt = $db->prepare($sql);
        $stmt->execute($params);
        return $stmt->rowCount();
    }
}