Entity

Base usage

You can describe wrappers for data structures with Entity

from corm import Storage, Entity


class User(Entity):
    id: int
    name: str
    description: str = 'cool guy'


storage = Storage()
john = User({'id': 1, 'name': 'John', 'address': 'kirova 1'}, storage)
john.name = 'Not John'

assert john.dict() == {
    'id': 1, 'name': 'Not John',
    'address': 'kirova 1', 'description': 'cool guy',
}

Note

You don't need to describe full data structure, only fields you need, rest corm leave as is. In example above address key

Fields

To set additional settings for any entity fields there is Field class

from corm import Storage, Entity, Field


class User(Entity):
    id: int = Field(origin='user_id')
    name: str
    description: str = Field(default='user')


storage = Storage()
user = User(data={'user_id': 33, 'name': 'John'}, storage=storage)

assert user.id == 33
assert user.description == 'user'
assert user.dict() == {'user_id': 33, 'name': 'John', 'description': 'user'}

Default values

There are two ways to set default value, just set as class value or through default param of Field, Nested or KeyNested

from corm import Storage, Entity, Field


class Foo(Entity):
    inplace = 1
    in_field = Field(default=2)
    in_field_callable = Field(default=list)


storage = Storage()
foo = Foo(data={}, storage=storage)

assert foo.inplace == 1
assert foo.in_field == 2
assert foo.in_field_callable == []

Note

default also can be callable, corm call it each time when creating entity instance if value of field is not provided. But you can use it only with Field, Nested or KeyNested, inplace is not allowed

from corm import Storage, Entity


class Foo(Entity):
    inplace = list


storage = Storage()
foo = Foo(data={}, storage=storage)

assert foo.inplace == list    # still callable, not new empty list