Book Image

Learning PHP Data Objects

By : Dennis Popel
Book Image

Learning PHP Data Objects

By: Dennis Popel

Overview of this book

PDO is lighter, faster, and more powerful than existing PHP data abstraction interfaces. PDO is a common interface to different databases that must be used with a database-specific PDO driver to access a particular database server: the PDO extension does not provide a database abstraction by itself; it doesn't rewrite SQL, emulate missing database features, or perform any database functions using by itself. It performs the same role as other classic database abstraction layers such as ODBC and JDBC: it's a query abstraction layer that abstracts the mechanism for accessing a database and manipulating the returned records; each database driver that implements the PDO interface can also expose database-specific features as regular extension functions. ¬ PDO ships with PHP 5.1, and is available as an extension for PHP 5.0; it requires the new object-oriented features of PHP 5, and cannot run with earlier versions of PHP.This book will teach you how to use the PDO, including its advanced features. Readers need to be aware of the basics of data abstraction and should be familiar with PHP.
Table of Contents (13 chapters)

Chapter 4. Prepared Statements

In the previous chapters, we have looked at the basics of PDO, and you may have noticed that most of its functionality resembles the traditional extensions used to connect to databases. The only new thing is exceptions, but even that can be similar to traditional error handling.

In this chapter we will look at a new concept that was not present in PHP before PDO: prepared statements. We will see how they can further simplify our code and even lead to better performance. We will also look at how PDO works with BLOBs—all in a database-independent manner, of course.

Regarding our library management application, we will rewrite the edit/update functionality added in the previous chapter so as to facilitate prepared statements, as well as add support for book cover images, which we will keep in the database.

Prepared Statements

A prepared statement is a template for executing one or more SQL queries against the database. The idea behind prepared statements is that...