ORM Hero

Hello!
I am Simone Di Maulo
Software Engineer @ AdEspresso
OOP
FP
BEER
@toretto460

Why do you need
an ORM
?

IMPEDANCE
MISMATCH

RBDMS
Objects
Object reference
Integer
Float
Double
String
DateTime
…
Table Row
ForeignKey
Integer
Float
Double
String
Date
…
PHP

Author Book
Author
Book
Book

Common
mistake

Magic

Magic

> Mapping to a relational database involves lots of repetitive,
boiler-plate code.
A framework that allows me to avoid 80% of that is
worthwhile even if it is only 80%.
The problem is in me for pretending it's 100%.
http://martinfowler.com/bliki/OrmHate.html
- Martin Fowler -

HOW DOES IT
WORK ¿

METADATA

/**
* @ORMTable(name=“author")
* @ORMEntity
*/
class Author
{
/**
* @ORMColumn(name=“id", type=“string")
* @ORMId
*/
private $id;
/**
* @ORMColumn(name=“name", type="string", length=255)
*/
private $name;
/**
* @ORMOneToMany(targetEntity=“Book", mappedBy=“author",
* cascade={“persist"})
*/
private $books;
}
MAPPING

/** @ORMTable(name="book") @ORMEntity */
class Book
{
/**@ORMColumn(name="id", type="string") @ORMId()*/
private $id;
/**@ORMManyToOne(targetEntity="Author", inversedBy="books") */
private $author;
/**@ORMColumn(name="publisher", type="string", length=255) */
private $publisher;
/**@ORMColumn(name="title", type="string", length=255) */
private $title;
/**@ORMColumn(name="published_at", type="datetime",
* nullable=false)
*/
private $publishedAt;
}
MAPPING

IDENTITY
MAP

$em->find(Author::class, $authorId);

// query
$author1 = $em->find(Author::class, 1);
// no query
$author2 = $em->find(Author::class, 1);
$author1 === $author2

// bypass the identity map
// a query were submitted to the DB
$authorRepository->findByName($authorName);

IDENTIFIERS

$user = User::register(/*..*/);
$em->persist($user);
$em->flush()

$user = User::register(/*..*/);
$em->persist($user);
$em->flush()
UUId
Auto Increment
Sequence

$user = User::register(/*..*/);
$em->persist($user);
$em->flush()
UUId
Auto Increment
Sequence
echo $user->getId();
echo $user->getId();
echo $user->getId();

$user = User::register(/*..*/);
$em->persist($user);
$em->flush()
UUId
// null
// 1
// 1
Auto Increment
Sequence
echo $user->getId();
echo $user->getId();
echo $user->getId();

$user = User::register(/*..*/);
$em->persist($user);
$em->flush()
UUId
// null
// 1
// 1
Auto Increment
// null
// null
// 1
Sequence
echo $user->getId();
echo $user->getId();
echo $user->getId();

$user = User::register(/*..*/);
$em->persist($user);
$em->flush()
UUId
// 2840555c-54ab-aa68-96
// 2840555c-54ab-aa68-96
// 2840555c-54ab-aa68-96
// null
// 1
// 1
Auto Increment
// null
// null
// 1
Sequence
echo $user->getId();
echo $user->getId();
echo $user->getId();

Unit of work

Unit of Work
$this->em->persist($author);

DETECT
CHANGES

$author = $em->find(Author::class, $authorId);
$author->addBook(. . .);
$this->em->flush();
IMPLICIT
/**
* @Entity
* @ChangeTrackingPolicy(
* “DEFERRED_IMPLICIT"
* )
*/
class Author{}

/**
* @Entity
* @ChangeTrackingPolicy("DEFERRED_EXPLICIT")
*/
class Author{}
$this->em->persist($alessandro);
$this->em->flush();
EXPLICIT

use DoctrineCommonNotifyPropertyChanged,
DoctrineCommonPropertyChangedListener;
/**
* @Entity
* @ChangeTrackingPolicy(“NOTIFY")
*/
class Author implements NotifyPropertyChanged
{
private $_listeners = array();
public function addPropertyChangedListener(PropertyChangedListener
$listener)
{
$this->_listeners[] = $listener;
}
}
foreach ($this->_listeners as $listener) {
$listener->propertyChanged($this, $propName, $oldValue, $newValue);
}
NOTIFY

Read

DEMO
Thanks to https://github.com/Ocramius/Doctrine2StepHydration

DON’T
complain

caches DOMAIN
ENTITY MANAGER
UNIT OF WORK REPOSITORY
See DoctrineCache @ SymfonyDayIt 2015 - https://vimeo.com/144858752

caches DOMAIN
ENTITY MANAGER
UNIT OF WORK REPOSITORY
metadata
cache
sql cache
result
cache
identity
map
2° level
cache
See DoctrineCache @ SymfonyDayIt 2015 - https://vimeo.com/144858752

USE THE
RIGHT TOOL

consider alternatives for :
Reporting
Append only data
CQRS

QUESTIONS

THANKS
https://joind.in/talk/0cc4f