Models & Django Admin

We would like users to be able to create new blog posts through our site. These posts will need to be saved to a database. Django has built-in support for interacting with SQL databases through an Object-Relational-Mapping or ORM. In this model, rows in the database table are represented by Python objects called models. Let's create a model for our blog posts.

Open blog/models.py and add the following:

class Post(models.Model):
    title = models.CharField(max_length=100)
    body = models.TextField()
    public = models.BooleanField(default=True)
    created = models.DateTimeField(auto_now_add=True)

Django will automatically create and update the database table schema to match our model. It does this through database migrations which are files containing the SQL commands needed to configure the database.

To generate and apply migrations to create our Post table run the following command in the terminal. If your terminal is blocked by the python manage.py runserver command you can open a new terminal with the + button.

python manage.py makemigrations
python manage.py migrate

By default, Django uses SQLite as the database. You should see a db.sqlite3 file; this is where SQLite will store our data.

Django automatically creates an admin interface that we can use to interact with our database.

In order to login we need to create a super-user account. Hop back to the terminal and run:

python manage.py createsuperuser

Set the username and password to whatever you would like. You can leave email address blank.

You can now use that username and password to log in to the admin interface. To access the admin interface, go to http://127.0.0.1:8000/admin/. Once you are logged in you will see links to Groups and Users but not our Posts. This is because we haven't registered our Post model with the admin app. To do that open blog/admin.py and add the following:

from .models import Post

admin.site.register(Post)

If you refresh the admin interface in your browser you should now see a row for managing Posts. Click the Add link and create a few Posts. Once you are done you should see several posts listed as in the screenshot below. In the next stage we will render them on our website.

The admin interface can be highly customised. For example, we can make the table listing our posts more informative by displaying the title of the posts instead of "Post object". To do this replace admin.site.register(Post) line in blog/admin.py with:
```
@admin.register(Post)
class PostAdmin(admin.ModelAdmin):
    list_display = ['title', 'public', 'created']
```
Reload http://127.0.0.1:8000/admin/blog/post/ to see the effect.

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