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.

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Persistence in PHP with Doctrine ORM
Kevin Dunglas
Dec, 2013 | 114 pages
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Table of Contents (12 chapters)
Persistence in PHP with Doctrine ORM
Persistence in PHP with Doctrine ORM
Credits
Credits
About the Author
About the Author
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Getting Started with Doctrine 2
Getting Started with Doctrine 2
Prerequisites
Understanding the concepts behind Doctrine
Creating a project structure
Installing Composer
Installing Doctrine
Bootstrapping the app
Using Doctrine's Entity Manager
Configuring Doctrine command-line tools
Summary
2
Entities and Mapping Information
Entities and Mapping Information
Creating the Entity class
Generating getters and setters
Mapping with Doctrine annotations
Understanding Doctrine Mapping Types
Creating the database schema
Installing Data fixtures
Creating a simple UI
Summary
3
Associations
Associations
Getting started with the Doctrine associations
Understanding the @ManyToOne and @OneToMany annotations with the comment system
Understanding the @ManyToMany annotation with tags
Summary
4
Building Queries
Building Queries
Understanding DQL
Using the entity repositories
Getting started with Query Builder
Filtering by tag
Counting comments
Summary
5
Going Further
Going Further
Implementing inheritance
Getting started with events
Writing native queries
Summary
Index
Index

Understanding the @ManyToMany annotation with tags

Tags group posts by topics. A tag contains several posts, and a post has several tags. This is a Many-To-Many bidirectional association. Doctrine manages transparently the association table needed to store Many-To-Many relations at the SQL level. The MySQL schema that will be generated is shown in the following screenshot:

Creating the Tag entity class (inverse side)

The Tag entity class has only two properties:

  • name: This is the name of the tag, it is unique, and is the identifier of the entity

  • posts: This is the collection of posts associated with this tag

The following are the steps to create the Tag entity class:

  1. Create a Tag.php file in the src/Blog/Entity/ location that contains the entity class using the following code snippet:

    <?php

namespace Blog\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping\Entity;
use Doctrine\ORM\Mapping\Column;
use Doctrine\ORM\Mapping\Id;
use Doctrine\ORM\Mapping\ManyToMany...
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