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)

Creating the Entity class

As explained in Chapter 1, Getting Started with Doctrine 2, a Doctrine entity is just a PHP object that will be saved in the database. Doctrine annotations are added in the PHP DocBlock comments of the Entity class properties. Annotations are used by Doctrine to map the object to the related database's table and properties to columns.


The original purpose of DocBlocks is integrating technical documentation directly in the source code. The most popular documentation generator that parses DocBlocks is phpDocumentator which is available on this website:

Each entity, once persisted through Doctrine, will be related to a row of the database's table.

Create a new file Post.php containing our entity class in the src/Blog/Entity/ location with the following code:


  namespace Blog\Entity;

  use Doctrine\ORM\Mapping\Entity;
  use Doctrine\ORM\Mapping\Table;
  use Doctrine\ORM\Mapping\Index;
  use Doctrine\ORM\Mapping\Id;
  use Doctrine...