One to Many
===========

The one to many relationship is similar to the may to one relationship except
that the role of the child and parent is swapped.

.. seealso::

    :ref:`one-to-many`
      OpenAlchemy documentation for one to many relationships.

    `SQLAlchemy One to Many <https://docs.sqlalchemy.org/en/13/orm/basic_relationships.html#one-to-many>`_
      SQLAlchemy documentation for one to many relationships.

The following example defines a one to many relationship between *Employee*
and *Division*:

.. literalinclude:: ../../../../examples/relationship/one_to_many/example-spec.yml
    :language: yaml
    :linenos:

The following file uses OpenAlchemy to generate the SQLAlchemy models:

.. literalinclude:: ../../../../examples/relationship/one_to_many/models.py
    :language: python
    :linenos:

The SQLAlchemy models generated by OpenAlchemy are equivalent to the following
traditional models file:

.. literalinclude:: ../../../../examples/relationship/one_to_many/models_traditional.py
    :language: python
    :linenos:

OpenAlchemy will generate the following typed models:

.. literalinclude:: ../../../../examples/relationship/one_to_many/models_auto.py
    :language: python
    :linenos: