A new version of openapi-SQLAlchemy has been release which adds support for $ref for columns. The package now supports openapi schemas such as the following:
components: schemas: Id: type: integer description: Unique identifier for the employee. example: 0 Employee: description: Person that works for a company. type: object properties: id: $ref: "#/components/schemas/Id" name: type: string description: The name of the employee. example: David Andersson.
If you are interested in how this was accomplished with decorators and recursive programming, the following article describes the implementation: Python Recursive Decorators.