magomogo/domain-model

A way to make domain-specific models persistent

Persisted models

, _(*1)

Intro

• I don't like ActiveRecord because of tight coupling with the database,
• I am not so comfortable with Data mappers because a mapper breaks model encapsulation,
• I like the idea to keep 'The State' separately from the logic.

Here is the way

The concept

To implement an entity, one should create two classes: Model and Properties. Model class contains domain-specific logic only. All state that should persist is located in Properties. Model has its Properties aggregated:, _(*2)

class Model implements ModelInterface
{
    /**
     * @var Properties
     */
    private $properties;

    public function __construct($properties)
    {
         $this->properties = $properties;
    }
}

This library takes care about the Properties, all its public fields and also relations can be saved/loaded in the Containers. Currently there is SqlDb, CouchDb, and Memory container., _(*3)

It is recommended to declare Model's constructor signature that doesn't allow to create an instance that makes no sense from the business logic point of view., _(*4)

$person = new Person\Model($propertiesBag);
$employee = new Employee\Model($company, $propertiesBag);

source: Person\Model | Employee\Model, _(*5)

Obvious responsibilities

To achieve persistency we don't need to store A model, it is necessary to store its properties., _(*6)

// save/update
$dbContainer = new Persisted\Container\SqlDb($connection);
$person->save($dbContainer);

// load
$persistedPerson = Person\Model::load($dbContainer, $id);

source: Persisted\Container\SqlDb, _(*7)

Handling user input with 'Editors', 'A Editor' is kind of a Container., _(*8)

$editor = new ProfileEditor($person);
// validation here
$editor->edit($userInput);

$editedPerson = Person\Model::load($editor);
$editedPerson->save($dbContainer);

Strong separation between different types of object relations

For example person properties can have contact info aggregated, it gets stored and updated together with person:, _(*9)

$contactInfoModel = new ContactInfo\Model($contactInfoProperties);

$personProperties = array(
    'name' => 'John',
    'contactInfo => $contactInfoModel
);

On the other hand, there is a person who's working in a company. These objects are connected by foreign key and created/updated separately., _(*10)

$company->save($dbContainer);
$employee = new Employee\Model($company, $employeeProperties);

// this won't update the company, but create one-to-many reference company -> person in the container
$employee->save($dbContainer);

A model can have a list of another models connected. This so-called many-to-many relation is possible using Collections., _(*11)

$collection = new Keymarker\Collection;
$collection['Example'] = new Keymarker\Model(new Keymarker\Properties(array('name' => 'Example'));

Examples

See test cases to learn recommended usage:, _(*12)

• Simply a Model with properties Company/ModelTest.php
• A Person having CreditCard aggregated, a Person that can be tagged with Keymarkers Person/ModelTest.php
• An Employee working in a Company Employee/ModelTest.php
• Keymarker model that has natural keys Keymarker/ModelTest.php, Keymarker/PropertiesTest.php
• Load/Create/Update/Save a persistent model ModelPersonEditorWorkflowTest.php

...the work is in progress..., _(*13)