Doctrine For Beginners

Who am I?
- CTO of MoreCommerce.com
- Using PHP for 15 years
- Involved with Doctrine and
Symfony development for 10
years

What is MoreCommerce?
- E-commerce seller tools and
consumer marketplaces.
- Wholly owned subsidiary of
Alibaba Group
- 100,000 Sellers
- 80M Active Shoppers
- Billions in GMV runs through
MoreCommerce platforms

● Open source PHP project started in 2006
● Initially only an Object Relational Mapper
● Evolved to become a collection of high
quality PHP packages focused on
databases and persistence related
functionality
What is Doctrine?

$ composer create-project symfony/skeleton:4.1.*
doctrine-for-beginners
$ cd doctrine-for-beginners
Create New Symfony Project

$ composer require symfony/orm-pack
Install Doctrine

$ composer require symfony/maker-bundle --dev
Install MakerBundle

DATABASE_URL=mysql://username:password@127.0.0
.1:3306/doctrine-for-beginners
Configure Database URL
Customize the DATABASE_URL environment variable in the .env file in the
root of your project. In this example we are connecting to MySQL.

Supported Databases
● MySQL
● MariaDB
● SQLite
● PostgreSQL
● SQL Server
● Oracle
● SQL Anywhere
● DB2

DATABASE_URL=sqlite:///%kernel.project_dir%/va
r/data.db
Using SQLite
Change the DATABASE_URL in the .env file to look like this if you want to
use SQLite.

$ php bin/console doctrine:database:create
Created database `doctrine-for-beginners`
for connection named default
Create Your Database

$ php bin/console doctrine:migrations:generate
A database migration is an incremental, reversible change to a relational
database schema.
You define the change to your database schema in a PHP class. Use the
doctrine:migrations:generate command to generate a new blank migration.
What is a Database Migration?

Generated Database Migration
final class Version20181012002437 extends AbstractMigration
{
public function up(Schema $schema) : void
{
// this up() migration is auto-generated, please modify it to your needs
}
public function down(Schema $schema) : void
{
// this down() migration is auto-generated, please modify it to your needs
}
}

Write Your Migration
{
$usersTable = $schema->createTable('user');
$usersTable->addColumn('id', 'integer', ['autoincrement' => true, 'notnull' => true]);
$usersTable->addColumn('username', 'string', ['length' => 255]);
$usersTable->setPrimaryKey(['id']);
}
{
$schema->dropTable('user');
}

Write Your Migration
{
$this->addSql('CREATE TABLE user (id INT AUTO_INCREMENT NOT NULL,
username VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET
utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB');
}
{
$this->addSql('DROP TABLE user');
}

$ php bin/console doctrine:migrations:migrate
Application Migrations
WARNING! You are about to execute a database migration that could result in schema
changes and data loss. Are you sure you wish to continue? (y/n)y
Migrating up to 20181012002437 from 0
++ migrating 20181012002437
-> CREATE TABLE user (id INT AUTO_INCREMENT NOT NULL, username VARCHAR(255) NOT
NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE
= InnoDB
++ migrated (0.04s)
------------------------
++ finished in 0.04s
++ 1 migrations executed
++ 1 sql queries
Run Your Migration

$ php bin/console doctrine:migrations:migrate prev
WARNING! You are about to execute a database migration that could result in schema
changes and data loss. Are you sure you wish to continue? (y/n)y
Migrating down to 0 from 20181012002437
-- reverting 20181012002437
-> DROP TABLE user
-- reverted (0.05s)
------------------------
++ 1 sql queries
Revert Your Migration

$ php bin/console make:controller UsersController
Generate Controller
We need a place to play around so let’s use the MakerBundle to generate a
UsersController

AppControllerUsersController
class UsersController extends AbstractController
{
/**
* @Route("/users", name="users")
*/
public function index()
{
return $this->json([
'message' => 'Welcome to your new controller!',
'path' => 'src/Controller/UsersController.php',
]);
}
}

Create Users
{
/**
* @Route("/users/create", name="users_create")
*/
public function create(Connection $connection, Request $request)
{
$connection->insert('user', ['username' => $request->request->get('username')]);
'success' => true,
'message' => sprintf('Created %s successfully!', $request->request->get('username')),
]);
}
}

$ curl --data "username=jon"
http://localhost/users/create
{
"success":true,
"message":"Created jon successfully!"
}
$ curl --data "username=ryan"
http://localhost/users/create
{
"success":true,
"message":"Created ryan successfully!"
}
Create Users

Read Users
{
/**
*/
public function users(Connection $connection)
{
$users = $connection->fetchAll('SELECT * FROM user');
return $this->json($users);
}
}

$ curl http://localhost/users
[
{
"id":"1",
"username":"jon"
},
{
"id":"2",
"username":"ryan"
}
]
Read Users

Read Single User
{
/**
* @Route("/users/{username}", name="user")
*/
public function user(Connection $connection, string $username)
{
$users = $connection->fetchAll(
'SELECT * FROM user WHERE username = "' . $username . '"'
);
}
}

STOP! SQL Injection
{
/**
*/
{
'SELECT * FROM user WHERE username = "' . $username . '"'
);
}
}
SQL
Injection

Use Parameter Placeholders
{
/**
*/
{
'SELECT * FROM user WHERE username = :username',
['username' => $username]
);
}
}

$ php bin/console make:entity User
Generating a User Entity
Generate a User entity with property named username that is a string and
has a max length of 255 characters.
Generates the following files/classes:
- src/Entity/User.php (AppEntityUser)
- src/Repository/UserRepository.php (AppRepositoryUserRepository)

AppEntityUser
/**
* @ORMEntity(repositoryClass="AppRepositoryUserRepository")
*/
class User
{
/**
* @ORMId()
* @ORMGeneratedValue()
* @ORMColumn(type="integer")
*/
private $id;
/**
* @ORMColumn(type="string", length=255)
*/
private $username;
// getters and setters
}

Inject EntityManager
/**
* @Route("/users/create/{username}", name="users_create")
*/
public function create(EntityManagerInterface $em, Request $request)
{
$user = new User();
$user->setUsername($request->request->get('username'));
$em->persist($user);
$em->flush();
// ...
}

persist() and flush()
- persist() - schedules an object to be tracked by Doctrine
- flush() - calculates changes made to objects and commits
the changes to the database with SQL INSERT, UPDATE
and DELETE queries.

How does flush() work?
$trackedObjects = getTrackedObjects();
$changesets = [];
foreach ($trackedObjects as $trackedObject)
{
$oldValues = getOldValues($trackedObject);
$newValues = getNewValues($trackedObject);
$changesets[] = calculateChangeset($oldValues, $newValues);
}
commitChangesets($changesets);

AppRepositoryUserRepository
class UserRepository extends ServiceEntityRepository
{
public function __construct(RegistryInterface $registry)
{
parent::__construct($registry, User::class);
}
/*
public function findOneBySomeField($value): ?User
{
return $this->createQueryBuilder('u')
->andWhere('u.exampleField = :val')
->setParameter('val', $value)
->getQuery()
->getOneOrNullResult()
;
}
*/
}

Inject the UserRepository
/**
*/
public function users(UserRepository $userRepository)
{
$users = $userRepository->findAll();
return $this->json(array_map(function(User $user) {
return [
'username' => $user->getUsername(),
];
}, $users));
}

Entity Repository: Magic Methods
$user = $userRepository->findOneByUsername('jwage');
$user = $userRepository->findByFieldName('value');
Magic methods are implemented using __call(). When a method that does
not exist is called, the method name is parsed and a query is generated,
executed, and the results are returned.

Entity Repository: Find By
$users = $userRepository->findBy(['active' => 1]);

Entity Repository: Find One By
$users = $userRepository->findOneBy(['active' => 1]);

Entity Repository: Custom Methods
class UserRepository extends ServiceEntityRepository
{
/**
* @return User[]
*/
public function findActiveUsers() : array
{
return $this->createQueryBuilder('u')
->andWhere('u.active = 1')
->getQuery()
->execute();
;
}
}

$ php bin/console make:entity User
Modify Your Entity
Modify your User entity and add a property named twitter that is a string and
has a max length of 255 characters.

Modify Your Entity
class User
{
// ...
/**
* @ORMColumn(type="string", length=255, nullable=true)
*/
private $twitter;
// ...
}

$ php bin/console make:migration
Generate Migration
Now that we’ve modified our User class and mapped a new twitter property,
when we run make:migration, a migration will be generated with the SQL
necessary to add the twitter column to the user table.
{
$this->addSql('ALTER TABLE user ADD twitter VARCHAR(255) DEFAULT
NULL');
}

$ php bin/console doctrine:migrations:migrate
WARNING! You are about to execute a database migration that could result in
schema changes and data loss. Are you sure you wish to continue? (y/n)y
Migrating up to 20181012041720 from 20181012002437
++ migrating 20181012041720
-> ALTER TABLE user ADD twitter VARCHAR(255) DEFAULT NULL
++ migrated (0.07s)
------------------------
++ 1 sql queries
Run Your Migration

Update Entities
/**
* @Route("/users/update/{username}", name="users_update")
*/
public function update(UserRepository $userRepository, EntityManagerInterface $em, Request $request, string
$username)
{
$user = $userRepository->findOneByUsername($username);
$user->setUsername($request->request->get('username'));
$user->setTwitter($request->request->get('twitter'));
$em->flush();
'success' => true,
'message' => sprintf('Updated %s successfully!', $username),
]);
}

$ curl --data "username=ryan&twitter=weaverryan"
http://localhost/users/update/ryan
{
"Success":true,"message":
"Updated ryan successfully!"
}
Update Entities

Use Twitter Property
/**
*/
public function users(UserRepository $userRepository)
{
$users = $userRepository->findAll();
return $this->json(array_map(function(User $user) {
return [
'twitter' => $user->getTwitter(),
];
}, $users));
}

$ curl http://localhost/users
[
{
"username":"jon",
"twitter":null
},
{
"username":"ryan",
"twitter":"weaverryan"
}
]
Use Twitter Property

Read Single User
/**
*/
public function user(UserRepository $userRepository, string $username)
{
$user = $userRepository->findOneByUsername($username); // magic method
'twitter' => $user->getTwitter(),
]);
}

$ curl http://localhost/users/ryan
{
"username":"ryan",
"twitter":"weaverryan"
}
Read Single User

Programmatic Schema Inspection

Inspect your Database Schema
/**
* @Route("/schema", name="schema")
*/
public function schema(Connection $connection)
{
$schemaManager = $connection->getSchemaManager();
$tables = $schemaManager->listTables();
$data = [];
foreach ($tables as $table) {
$data[$table->getName()] = [
'columns' => [],
];
$columns = $schemaManager->listTableColumns($table->getName());
foreach ($columns as $column) {
$data[$table->getName()]['columns'][] = $column->getName();
}
}
return $this->json($data);
}

$ curl http://localhost/schema
{
"migration_versions":{
"columns":["version"]
},
"user":{
"columns":["id","username","twitter"]
}
}
Inspect your Database Schema

When To Use Transactions
When you have a unit of work that needs to be
ALL OR NOTHING. Meaning, if one part of a
larger process fails, all changes made to the
database are rolled back.

$connection->beginTransaction();
try {
$connection->executeQuery('UPDATE users SET twitter = :twitter WHERE username = :username', [
'twitter' => 'jwage',
'username' => 'jwage'
]);
// execute other updates
// do something that throws an Exception and both updates will be rolled back
$connection->commit();
} catch (Exception $e) {
$connection->rollBack();
throw $e;
}
Example Transaction

$connection->transactional(function(Connection $connection) {
$connection->executeQuery('...');
// do some stuff
// do something that throws an exception
});
Example Transaction

DQL: Doctrine Query Language
Query language similar to SQL except in DQL
you think in terms of your mapped entities and
class properties instead of tables and columns.
The DQL language is parsed and transformed
to platform specific SQL queries.
What is it?

DQL: Query Builder
$qb = $entityManager->createQueryBuilder()
->select('u')
->from(User::class, 'u')
->where('u.username = :username')
->setParameter('username', 'jwage');
/** @var User[] $users */
$users = $qb->getQuery()->execute();

DQL -> SQL
SELECT u FROM AppEntitiesUser u WHERE u.status = :status
SELECT u0_.id AS id_0, u0_.username AS username_1,
u0_.twitter AS twitter_2 FROM user u0_ WHERE u0_.username =
?
DQL
SQL

Writing DQL Manually
$query = $entityManager->createQuery(
'SELECT u FROM AppEntityUser u WHERE u.username = :username'
);
/** @var User[] $users */
$users = $query->execute([
'username' => 'jon',
]);

Advanced DQL Examples
SELECT u FROM User u WHERE u.phonenumbers IS EMPTY
SELECT u FROM User u WHERE SIZE(u.phonenumbers) > 1
SELECT u.id FROM User u WHERE :groupId MEMBER OF
u.groups
SELECT u.id FROM User u WHERE EXISTS (SELECT
p.phonenumber FROM Phonenumber p WHERE p.user = u.id)

DQL: Data Transfer Objects
class CustomerDTO
{
public function __construct($name, $email, $city, $value = null)
{
// Bind values to the object properties.
}
}
$query = $em->createQuery('SELECT NEW CustomerDTO(c.name, e.email, a.city)
FROM Customer c JOIN c.email e JOIN c.address a');
/** @var CustomerDTO[] $users */
$users = $query->getResult();

Native Raw SQL
use DoctrineORMEntityManagerInterface;
$rsm = new ResultSetMapping();
$rsm->addEntityResult(User::class, 'u');
$rsm->addFieldResult('u', 'id', 'id');
$rsm->addFieldResult('u', 'username', 'username');
$rsm->addFieldResult('u', 'twitter', 'twitter');
$query = $em->createNativeQuery(
'SELECT id, username, twitter FROM user WHERE username = :username', $rsm
);
$query->setParameter('username', 'ryan');
/** @var User[] $user */
$users = $query->getResult();

Questions?
Connect with me
https://twitter.com/jwage
https://github.com/jwage
https://jwage.com

Doctrine For Beginners

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