Mixin ClassesΒΆ
SQLAlchemy supports mixin classes for models to add functionality. OpenAlchemy
supports this through the x-mixins
extension property that may define
one or more importable class to mix into the model class.
See also
- Mixin Classes
OpenAlchemy documentation for the
x-mixins
value.
The following example adds the sqlalchemy_mixins.TimestampsMixin
to
the Employee
model:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 | openapi: "3.0.0" info: title: Test Schema description: API to illustrate the OpenAlchemy mixin feature. version: "0.1" paths: /employee: get: summary: Used to retrieve all employees. responses: 200: description: Return all employees from the database. content: application/json: schema: type: array items: "$ref": "#/components/schemas/Employee" components: schemas: Employee: description: Person that works for a company. type: object x-tablename: employee x-mixins: sqlalchemy_mixins.TimestampsMixin properties: id: type: integer description: Unique identifier for the employee. example: 0 x-primary-key: true x-autoincrement: true name: type: string description: The name of the employee. example: David Andersson x-index: true division: type: string description: The part of the company the employee works in. example: Engineering x-index: true salary: type: number description: The amount of money the employee is paid. example: 1000000.00 required: - name - division |
The following file uses OpenAlchemy to generate the SQLAlchemy models:
1 2 3 | from open_alchemy import init_yaml init_yaml("example-spec.yml", models_filename="models_auto.py") |
The SQLAlchemy models generated by OpenAlchemy are equivalent to the following traditional models file:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | import sqlalchemy as sa from sqlalchemy.ext.declarative import declarative_base from sqlalchemy_mixins import TimestampsMixin Base = declarative_base() class Employee(Base, TimestampsMixin): """Person that works for a company.""" __tablename__ = "employee" __abstract__ = False id = sa.Column(sa.Integer, primary_key=True, autoincrement=True) name = sa.Column(sa.String, index=True) division = sa.Column(sa.String, index=True) salary = sa.Column(sa.Float) |
OpenAlchemy will generate the following typed models:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 | """Autogenerated SQLAlchemy models based on OpenAlchemy models.""" # pylint: disable=no-member,super-init-not-called,unused-argument import typing import sqlalchemy from sqlalchemy import orm from open_alchemy import models class _EmployeeDictBase(typing.TypedDict, total=True): """TypedDict for properties that are required.""" name: str division: str class EmployeeDict(_EmployeeDictBase, total=False): """TypedDict for properties that are not required.""" id: int salary: typing.Optional[float] class TEmployee(typing.Protocol): """ SQLAlchemy model protocol. Person that works for a company. Attrs: id: Unique identifier for the employee. name: The name of the employee. division: The part of the company the employee works in. salary: The amount of money the employee is paid. """ # SQLAlchemy properties __table__: sqlalchemy.Table __tablename__: str query: orm.Query # Model properties id: "sqlalchemy.Column[int]" name: "sqlalchemy.Column[str]" division: "sqlalchemy.Column[str]" salary: "sqlalchemy.Column[typing.Optional[float]]" def __init__( self, name: str, division: str, id: typing.Optional[int] = None, salary: typing.Optional[float] = None, ) -> None: """ Construct. Args: id: Unique identifier for the employee. name: The name of the employee. division: The part of the company the employee works in. salary: The amount of money the employee is paid. """ ... @classmethod def from_dict( cls, name: str, division: str, id: typing.Optional[int] = None, salary: typing.Optional[float] = None, ) -> "TEmployee": """ Construct from a dictionary (eg. a POST payload). Args: id: Unique identifier for the employee. name: The name of the employee. division: The part of the company the employee works in. salary: The amount of money the employee is paid. Returns: Model instance based on the dictionary. """ ... @classmethod def from_str(cls, value: str) -> "TEmployee": """ Construct from a JSON string (eg. a POST payload). Returns: Model instance based on the JSON string. """ ... def to_dict(self) -> EmployeeDict: """ Convert to a dictionary (eg. to send back for a GET request). Returns: Dictionary based on the model instance. """ ... def to_str(self) -> str: """ Convert to a JSON string (eg. to send back for a GET request). Returns: JSON string based on the model instance. """ ... Employee: typing.Type[TEmployee] = models.Employee # type: ignore |
See also