.. _changing-models:

=================
 Changing Models
=================

See online documentation at https://docs.djangoproject.com/en/3.0/topics/migrations/

The steps below can be seen in commit https://github.molgen.mpg.de/EditionOpenAccess/django-eoapublications/commit/9c362de9f2cd104e278d0fbdca59fed75dd331e6

models.py
=========

The paragraph style 'divider' is to be added. In ``models.py``, add it to the ``KINDS`` array::

      KINDS = (
        ('eoaparagraph', 'Paragraph'),
        # ...
        ('eoadivider', 'Divider')
    )

Make the migration, specifying a message and the app::

  $ python manage.py makemigrations --name add_divider eoapublications
  #  Migrations for 'eoapublications':
  #     eoapublications/migrations/0003_add_divider.py
  #       - Alter field Kind on element

Then, migrate::

  python manage.py migrate

Now, the new paragraph type is available:

.. image:: /_static/new_paragraph_kind.png
   :scale: 50 %
   :alt: New paragraph kind added to model
   :align: center


publicationimport
=================

The ``publicationimport`` script has to be made aware of a new field and how it should deal with it (see https://github.molgen.mpg.de/EditionOpenAccess/django-eoapublications/commit/9c362de9f2cd104e278d0fbdca59fed75dd331e6#diff-f56c1a061762893512c03db32248d05f).

templates
=========

Additionally, the templates need to know how to render the new field (see https://github.molgen.mpg.de/EditionOpenAccess/django-eoapublications/commit/9c362de9f2cd104e278d0fbdca59fed75dd331e6#diff-73961337cb59c4fc10c6600d78ce2f38 and https://github.molgen.mpg.de/EditionOpenAccess/django-eoapublications/commit/9c362de9f2cd104e278d0fbdca59fed75dd331e6#diff-9da26c07709b591cbc6db9940b44cfe2).


Distributing models
-------------------

In order to apply these changes to other running instances, commit the migration together with the other changes. See :ref:`update-components` on how to update and migrate changes.