Models

banana.models contains the Django ORM models. These Object Oriented representation of a TRAP database. Since you don’t initialise the TRAP database using Django, we need to manually keep the Django models in sync with the TRAP schema. Below we describe a procedure on how to do this.

Updating the model

You need to update the banana/models.py file to reflect the new database structure. The easy way to do this is as follows:

  • Generate a new database with the schema version you want to upgrade to (using, eg, tkp-manage.py initdb). Either MonetDB or Postgres is fine.

  • Get a Banana installation which is able to connect to your database. You’ll need to edit project/settings/local.py to set the appropriate hostname, port and password for MonetDB and/or for Postgres. Banana will build a list of all the databases on the host you specify, based on the assumption that the database name, username and password are all the same.

  • Within your banana directory, dump a set of models representing your new database by running:

    $ ./manage.py inspectdb --database=<dbname> > banana/models_new.py

  • Using your favourite tool, update banana/models.py to reflect the additions in banana/models_new.py. Note that banana/models.py has a bunch of useful customization which we don’t want to lose. don’t replace it with the new version, but rather carefully compare it with the new models and merge only the relevant changes.

  • Update the schema_version variable defined in banana/models.py to reflect the new schema.

  • Check for any templates (stored in banana/templates) which are using model fields which you’ve just removed or renamed, and modify them to use the new models.

  • Commit your changes, submit a pull request, and have a cup of tea.