Sunhill ORM
What is ORM?
ORM stands for Object-Relational-Mapper and means, that is possible to store objects into a database. The laravel framework already has an ORM component called Eloquent, but it lacks of some functionallity.
The philosphy behind ORM
Motivation
The main motivation of creating the orm framework was, that I didn't like, that there is no inheritance in laravel's eloquent. You can have a table 'animal' and a table 'birds' but no direct relation in the form a bird->animal (a bird is an animal). The managing of this relation creates some overhead so for more simple tables there is a concept similar to eloquent called collections.
Difference between a collection and an object
While an object provides the possibility to create a relation structures between classes (like a bird is an animal) a collection is just a plain old flat class to database mapper. You can create a collection like "bird" but it won't store any information that a bird is an animal. For simple data that needs no hirachy this is sufficient.Difference between collections/objects and properties
Long story short collections and objects manage (and collect) different properties. A property is the smallest part of information (like integer, string) while the object collects different properties. Lets say we have a collection called "animal". This collection can have the properties "name", "weight", "owner" and so on. It is even possible to create a property of a collection or object. In the example of the animals you can add a property calles "father" and "mother" with the type of "animal".
Difference between collections/objects and storages
While the collections or objects store and manage the informations the storage takes care on how this information are made persistant. The typical storage is a database (although it could be a flat file). When a collection/object is told to store itself it creates a storage internally and passes its data to this storage. The storage in turn handles the moving of the data into the storage (e.g. database).
Summary
- A property is a single piece of information. It takes care of validating the information.
- A collection is an assemblage of properties or pieces of information. It takes care of accessing the properties.
- A storage is a possibility to store collections into a persistant storage (like a database). It takes care of passing the data from the collections to the physical storage.
