Attributes

With attributes it is possible to extend classes by additional fields. Another benifit is to share the same entity between totally differnt classes (like a rating). Due the more complex nature of attributes it's more efficient to put properties, that should be assigned to all members of a class into the class itself and not in an attribute.

Usage

Name and type

Attributes have to be creates before they can be used. To manage attributes there is the attribues facade. To define a new attribute it needs a name and a type. The naming schema is the same as for properties. If a class defines a property with the same name this attribute can't be assigned to an object of this class (because the orm system will always prefer the built-in property). The type can be any of the scalar property types like integer, string, boolean, enum, date, datetime, time or float. Arrays or maps can't be used at attributes.

Creation

To create an attribute for later usasge you can use the attributes query of the attributes facade:

...
use Sunhill\ORM\Facades\Attributes;
...
Attributes::query()->insert(['name'=>'attribute_name','type'=>PropertyInteger::class]);
...

This creates an attribute with the name attribute_name of the type integer. To restrict the usage of this attribute to certain classes you can add one or more classes that are allowed for this attribute

...
use Sunhill\ORM\Facades\Attributes;
...
Attributes::query()->insert(['name'=>'attribute_name','type'=>PropertyInteger::class,'allowed_classes'=>SomeClass::class]);
...

Assigning to an object

If you want to assign the previous created attribute to an object just use it like any other property:

$object = new SomeClass();

$object->attribute_name = 10;

The orm system searches for attributes whenever you try to assign a property that does not exist in the class.

Queries

Attributes can be queries via the attributes facade.

Attributes::query()->get();   // Returns all attributes
Attributes::query()->count(); // Returns the number of attributes
Attributes::query()->where('name', 'attribute_name')->first(); // Returns the attribute with the name **attribute_name** or null if no such attribute exists.
Attributes::query()->where('assigned')->get(); // Return all attributes that are assigned to at least one object
Attributes::query()->where('allowed_classes','matches',SomeClass::class)->get(); // Returns all attributes that are allowed for SomeClass or one of its children
Attributes::query()->insert([...]); // Inserts a new attribute (see above)
Attributes::query()->where('name','attribute_name')->update(['attribute_name'=>'new_name']); // Renames the attribute **attribute_name** to **new_name**
Attributes::query()->where('name','attribute_name')->delete(); // Deletes the attribute with the name **attribute_name**
Attributes::query()->delete(); // **Be careful:** Deletes all attributes