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)

Mapping with Doctrine annotations

Post is a simple class with four properties. The setter for $id isn't actually generated. Doctrine populates the $id instance variable directly in the entity hydration phase. We will see later how we delegate the ID generation to the DBMS.

Doctrine annotations are imported from the \Doctrine\ORM\Mapping namespace with use statements. They are used in DocBlocks to add mapping information to the class and its properties. DocBlocks are just a special kind of comment starting with /**.

Knowing about the @Entity annotation

The @Entity annotation is used in the class-level DocBlock to specify that this class is an entity class.

The most important attribute of this annotation is repositoryClass. It allows specifying a custom entity repository class. We will learn about entity repositories, including how to make a custom one, in Chapter 4, Building Queries.

Understanding the @Table, @Index, and @UniqueConstraint annotations

The @Table annotation is optional. It can be...