ddapp

Set up the app

Make sure Python 3 and psycopg2 are installed.

Set up a containerized instance of PostgreSQL:

docker run -d -p 5432:5432 -e PG_USER=devuser -e PG_PASSWORD=password -e PG_DATABASE=ddapp --name=ddapp crunchydata/crunchy-postgres-appdev

If you have a SQL script to implement the database schema check that devuser is the schema owner.

Otherwise execute these statements after setting up the database:

GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO devuser;
GRANT ALL PRIVILEGES ON ALL sequences IN SCHEMA public TO devuser;

Set up a virtual environment and add to project:

Django 2.2.12
django-crispy-forms

Start a new project:

django-admin startproject ddmanager

Start a new app:

py manage.py startapp manager

Run the initial migration to create database tables needed by default Django applications:

py manage.py migrate

Add the app and crispy_forms to INSTALLED_APPS in settings.py:

INSTALLED_APPS = [
    'manager',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'crispy_forms',
]

Set database connection parameters:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'ddapp',
        'USER': 'devuser',
        'PASSWORD': 'password',
        'HOST': '127.0.0.1',
        'PORT': '5432',
    }
}

Make sure you've also set a template pack (CSS framework) in settings.py:

CRISPY_TEMPLATE_PACK = 'bootstrap4'

Create a superuser before creating any models (or doing anything really):

python manage.py createsuperuser

Use inspectdb to autogenerate a Django model module to standard output. On the command line you can pipe it to models.py:

py manage.py inspectdb > models.py

Other notes

• Our registration template (/manager/templates/manager/register.html) is namespaced just in case.

• Django docs says managed = False in model class meta only pertains to creation and deletion of table, but it also applies to alter. If you don't change it, no migrations happen.

• Django doesn't handle Postgres composite primary keys.

• Django doesn't do a good job of altering table keys if it didn't create them. If Postgres already has the correct keys just take them out of the migration file.

• Creating a new auto-generated column on a table asks for a default value during the migration. Just delete the default argument in the migration file.