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 2. Entities and Mapping Information

In the previous chapter, we discovered the concepts behind Doctrine, we learned how to use Composer to install it, we set up the Doctrine Command Line Tools and we dived into the Entity Manager.

In this chapter, we will cover the following topics:

  • Creating our first entity class

  • Mapping it to its related database table and columns with annotations

  • Using a command helper provided by Doctrine to automatically generate the database schema

  • Creating some fixtures data and dealing with the Entity Manager to display our data in a web user interface

Because we are building a blog, our main entity class will be called Post, as shown in the following figure:

Our Post entity class has the following four properties:

  • id: The unique identifier of the post across the database table (and the blog)

  • title: The post's title

  • body: The post's body

  • publicationDate: The date of publication of the post