*******************************************************************************
Database
*******************************************************************************

Overview
===============================================================================

The database used in this project is `postgreSQL <https://www.postgresql.org/>`_

Connection
===============================================================================

*If docker-compose is running*

.. code-block:: bash

    docker exec -f docker-compose.prod.yml -it emergen-db_db_1 psql -U postgres -W postgres

UML schemas
===============================================================================

To generate UML schema in png and store in `static-apps/img/` (the image is thus usable in the application).
We use `django-extensions <https://github.com/django-extensions/django-extensions>`_ , `pydotplus <https://pypi.org/project/pydotplus/>`_
and `graphviz <https://pypi.org/project/graphviz/>`_ .

Note : *Docker-compose must be running*

.. code-block:: bash

    docker-compose -f docker-compose.prod.yml  exec web python manage.py graph_models -a -o static-apps/img/EMERGEN-DB_models.png

**Result**

.. image:: https://gitlab.com/ifb-elixirfr/covid19/EMERGEN-DB/-/raw/master/static-apps/img/EMERGEN-DB_models.png
  :width: 100 %
  :alt: UML


Create table
===============================================================================

To create a table in the database, we use the Django ORM. In each application of
the Django project (:code:`home`, :code:`collector`, :code:`stats` and :code:`api`)
you will find a :code:`models.py` file. The declaration of the tables is done in these files.

Then you have to translate these tables (:code:`makemigrations`) and migrate the tables into the database.

.. warning::

    Docker and EMERGEN-DB must always be switched on !

.. code-block:: bash

    docker-compose exec web python manage.py makemigrations
    docker-compose exec web python manage.py migrate

Clear database (danger area)
===============================================================================

.. warning::
    Be careful, these actions are final and all data will be permanently lost !

If you want to delete the table and all the "translations" to make a clean database,
for example when fields of a table are updated, you can use the following commands :

.. warning::
    Did you read the warning below correctly?

.. code-block:: bash

    # Stop application
    docker-compose down # if EMERGEN-db is running

    # Delete database
    docker-compose rm db

    # Remove migrations django files
    find . -path "*/migrations/*.py" -not -name "__init__.py" -delete
    find . -path "*/migrations/*.pyc"  -delete

    # Start application
    docker-compose up

    # Make migration
    docker-compose exec web python manage.py makemigrations
    docker-compose exec web python manage.py migrate

    # Populate database
    docker-compose exec web python manage.py load_region
    docker-compose exec web python manage.py load_departement
    docker-compose exec web python manage.py load_description