Shepherding Banana through schema upgrades

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 bananaproject/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>, where is just the name of your database (in the case of MonetDB) or the string postgres_ followed by the name of your database (for Posgtres). This will print the new models to standard out: you'll probably want to redirect them to a file (say, models-new.py).
• Using your favourite tool, update banana/models.py to reflect the additions in models-new.py (that is, run vimdiff banana/models.py models-new.py or equivalent). Note that anana/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.

Updating the fixtures

The make the test suite pass after a schema change you need to update the fixtures also:

• Populate the database with some dataset, not too big but make sure all tables are populated (like transient).
• run ./manage.py dumpdata --database=postgres_gijs --indent=1 banana > testing/fixtures/initial_data.json to serialize the data into the fixture.
• Note that some libraries like astropy write things to stdout which ruins the json output. Check the json file to make sure there is no garbage at the start of the file.
• Run the test suite and check if all tests are passing
• If not, fix
• Issue pull request