Book Image

Persistence in PHP with Doctrine ORM

By : Kevin Dunglas
Book Image

Persistence in PHP with Doctrine ORM

By: Kevin Dunglas

Overview of this book

Doctrine 2 has become the most popular modern persistence system for PHP. It can either be used as a standalone system or can be distributed with Symfony 2, and it also integrates very well with popular frameworks. It allows you to easily retrieve PHP object graphs, provides a powerful object-oriented query language called DQL, a database schema generator tool, and supports database migration. It is efficient, abstracts popular DBMS, and supports PHP 5.3 features. Doctrine is a must-have for modern PHP applications. Persistence in PHP with Doctrine ORM is a practical, hands-on guide that describes the full creation process of a web application powered by Doctrine. Core features of the ORM are explained in depth and illustrated by useful, explicit, and reusable code samples. Persistence in PHP with Doctrine ORM explains everything you need to know to get started with Doctrine in a clear and detailed manner. From installing the ORM through Composer to mastering advanced features such as native queries, this book is a full overview of the power of Doctrine. You will also learn a bunch of mapping annotations, create associations, and generate database schemas from PHP classes. You will also see how to write data fixtures, create custom entity repositories, and issue advanced DQL queries. Finally it will teach you to play with inheritance, write native queries, and use built-in lifecycle events. If you want to use a powerful persistence system for your PHP application, Persistence in PHP with Doctrine ORM is the book you.
Table of Contents (12 chapters)

Chapter 1. Getting Started with Doctrine 2

The Doctrine project is a collection of libraries providing utilities to ease data persistence in PHP applications. It makes it possible to create complex model layers in no time that will be compatible with popular DBMS, including SQLite, MySQL, and PostgreSQL. To discover and understand Doctrine, we will create a small blog from scratch throughout this book that will mainly use the following Doctrine components:

  • Common provides utilities that are not in the PHP standard library including a class autoloader, an annotations parser, collections structures, and a cache system.

  • Database Abstraction Layer (DBAL) exposes a unique interface to access popular DBMS. Its API is similar to PDO (and PDO is used when possible). The DBAL component is also able to execute the same SQL query on different DBMS by internally rewriting the query to use specific constructs and emulate missing features.

  • Object Relational Mapper (ORM) allows accessing and managing relational database tables and rows through an object-oriented API. Thanks to it, we will directly manipulate PHP objects, and it will transparently generate SQL queries to populate, persist, update, and delete them. It is built on top of DBAL and will be the main topic of this book.


For more information on PHP Data Objects and the data-access abstraction layer provided by PHP, refer to the following link:

To learn Doctrine, we will build together a tiny blog engine with advanced features such as the following:

  • Posts list, creation, editing, and deletion

  • Comments

  • Tag filtering

  • Profiles for author of posts and comments

  • Statistics

  • Data fixtures

The following is a screenshot of the blog:

In this chapter, we will learn about the following topics:

  • Understanding concepts behind Doctrine

  • Creating the project's structure

  • Installing Composer

  • Installing Doctrine ORM, DBAL, and Common through Compose

  • Bootstrapping the app

  • Using Doctrine's Entity Manager

  • Configuring Doctrine command-line tools