Define Other Models
Let's continue to create our application. So, we continue to write our Models inside the models.py file.
from django.db import models
class Author(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
pen_name = models.CharField(max_length=100)
def __str__(self):
if self.pen_name:
return f"Author {self.pk}: {self.pen_name}"
else:
return f"Author {self.pk}: {self.first_name} {self.last_name}"
class Genre(models.Model):
format = models.CharField(max_length=50, unique=True)
def __str__(self):
return f"Literary genre {self.pk}: {self.format}"
class Book(models.Model):
COVER_CHOICES = [
("H", "Hard"),
("S", "Soft")
]
title = models.CharField(max_length=100, unique=True)
price = models.DecimalField(max_digits=5, decimal_places=2)
cover = models.CharField(max_length=1, choices=COVER_CHOICES)
def __str__(self):
return f"Book {self.pk}: {self.title}"
Note
An id field is automatically added as a primary key for each model instance. You don't need to declare it explicitly in your models.
We haven't created any relations between our Models yet, but we'll address this shortly.
1. In the Book model, you wish to add three new fields: 'publishing_date', 'rating', and 'quantity'. Which combination of field types is the most appropriate for these fields?
2. What is the primary purpose of the '__str__' method in a Django model?
Thanks for your feedback!
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Define Other Models
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Let's continue to create our application. So, we continue to write our Models inside the models.py file.
from django.db import models
class Author(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
pen_name = models.CharField(max_length=100)
def __str__(self):
if self.pen_name:
return f"Author {self.pk}: {self.pen_name}"
else:
return f"Author {self.pk}: {self.first_name} {self.last_name}"
class Genre(models.Model):
format = models.CharField(max_length=50, unique=True)
def __str__(self):
return f"Literary genre {self.pk}: {self.format}"
class Book(models.Model):
COVER_CHOICES = [
("H", "Hard"),
("S", "Soft")
]
title = models.CharField(max_length=100, unique=True)
price = models.DecimalField(max_digits=5, decimal_places=2)
cover = models.CharField(max_length=1, choices=COVER_CHOICES)
def __str__(self):
return f"Book {self.pk}: {self.title}"
Note
An id field is automatically added as a primary key for each model instance. You don't need to declare it explicitly in your models.
We haven't created any relations between our Models yet, but we'll address this shortly.
1. In the Book model, you wish to add three new fields: 'publishing_date', 'rating', and 'quantity'. Which combination of field types is the most appropriate for these fields?
2. What is the primary purpose of the '__str__' method in a Django model?
Thanks for your feedback!