Create model with foreign key in Django

2024-02-23 | Tag python django models

Model

For ForeignKey we must specify an on_delete option.

import uuid
from django.db import models
from django.urls import reverse
from django.contrib.auth import get_user_model

class Book(models.Model):
	# ...

class Review(models.Model):
    book = models.ForeignKey(
        Book,
        on_delete=models.CASCADE,
        related_name='reviews',
    )
    review = models.CharField(max_length=255)
    author = models.ForeignKey(
        get_user_model(),
        on_delete=models.CASCADE
    )

    def __str__(self):
        return self.review

We can set the related_name to make it easier to follow the foreign key relationship backwards on queries, note this name must be unique:

reviews = mybook.reviews.all();

Admin

In the one-to-many relationship, we can display the reviews as tabular inline in book:

from django.contrib import admin
from .models import Book, Review

class ReviewTabularInline(admin.TabularInline):
    model = Review

class BookAdmin(admin.ModelAdmin):
    inlines = [
        ReviewTabularInline
    ]
    list_display = ('title', 'author', 'price')

admin.site.register(Book, BookAdmin)

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