Django - Models Explained

I am trying to go through the official documentation of Django and read through every aspect of it in order to build a server using Django. The first section is Models

TL;DR

A Django model becomes a table and its rows in your database.

Explanation

1. Each model is a Python class that subclasses django.db.models.Model

from django.db import models

class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

You have just created a Person model with fields name first_name and last_name. If you use a database, Person is your table, and first_name and last_name are its rows. And an id is added automatically as a primary key for your convenience.

But the name of the table becomes myapp_person instead of person. If you want to want a table called person instead, you can write your model like this by using a Meta class.

from django.db import models

class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

    class Meta:
        db_table = 'person'

After creating a model, you have to make migrations with manage.py makemigrations and then manage.py migrate. The first command creates migration files which declares what you have done with your models.py like creating a table and rows or alternating rows. And the next command applies the changes to your database.

2. Fields

Each field takes a certain set of field-specific arguments. Some fields requires certain arguments while others do not. I feel like it is not really worth memorizing those, so you can find the information here

Certain arguments may come to you as you write more codes. For example, a CharField requires an max_length argument. If you add null=True as an argument to a field, Django will store empty values as NULL. If you add blank=True as an argument to a field, Django will store an empty value instead of using NULL.

There is also an argument called choices, which is a sequence of 2-tuples. Check the example below;

class Person(models.Model):
    SHIRT_SIZES = (
        ('S', 'Small'),
        ('M', 'Medium'),
        ('L', 'Large'),
    )
    name = models.CharField(max_length=60)
    shirt_size = models.CharField(max_length=1, choices=SHIRT_SIZES)

If you make a query to a Person class, person.shirt_size would give you S, M, or an L. If you call a function like person.get_shirt_size_display(), yow would get Small, Medium, or Large.

You can also use enumeration classes like below;

from django.db import models

class Runner(models.Model):
    MedalType = models.TextChoices('MedalType', 'GOLD, SILVER, BRONZE')
    name = models.CharField(max_length=60)
    medal = models.CharField(blank=True, choices=MedalType.choices, max_length=10)

There is an argument called verbose_name, which is automatically generated if you do not specify. I think you can use this as for your reference for you to help other developers what you were trying to do with this field.