- 1, Configuring the Database
in settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
}
}
- 2, Create a books app
python manage.py startapp books
and then the layout of dir.
\mypro
\books
\migrations
__init__.py
admin.py
apps.py
models.py
tests.py
views.py
\mypro
\templates
manage.py
- 3, Define Models
in models.py
from django.db import models
class Publisher(models.Model):
name = models.CharField(max_length=30)
address = models.CharField(max_length=50)
city = models.CharField(max_length=60)
state_province = models.CharField(max_length=30)
country = models.CharField(max_length=50)
website = models.URLField()
class Author(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=40)
email = models.EmailField()
class Book(models.Model):
title = models.CharField(max_length=100)
authors = models.ManyToManyField(Author)
publisher = models.ForeignKey(Publisher)
publication_date = models.DateField()
- 4, Install Models
in settings.py
INSTALLED_APPS = [
'books.apps.BooksConfig', # add this line
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
]
BooksConfigclass that Django created for you in theapps.pyfile.
- 5, validate the models
python manage.py check
If it's succeed, it would output
System check identified no issues (0 silenced).
- 6, Migrate database
When running
python manage.py makemigrations books
it outputs
Migrations for 'books':
0001_initial.py:
- Create model Author
- Create model Book
- Create model Publisher
- Add field publisher to book
Running
python manage.py sqlmigrate books 0001
it would output
BEGIN;
CREATE TABLE "books_author" (
"id" integer NOT NULL PRIMARY KEY AUTOINCREMENT,
"first_name" varchar(30) NOT NULL,
"last_name" varchar(40) NOT NULL,
"email" varchar(254) NOT NULL
);
CREATE TABLE "books_book" (
"id" integer NOT NULL PRIMARY KEY AUTOINCREMENT,
"title" varchar(100) NOT NULL,
"publication_date" date NOT NULL
);
CREATE TABLE "books_book_authors" (
"id" integer NOT NULL PRIMARY KEY AUTOINCREMENT,
"book_id" integer NOT NULL REFERENCES "books_book" ("id"),
"author_id" integer NOT NULL REFERENCES "books_author" ("id"),
UNIQUE ("book_id", "author_id")
);
CREATE TABLE "books_publisher" (
"id" integer NOT NULL PRIMARY KEY AUTOINCREMENT,
"name" varchar(30) NOT NULL,
"address" varchar(50) NOT NULL,
"city" varchar(60) NOT NULL,
"state_province" varchar(30) NOT NULL,
"country" varchar(50) NOT NULL,
"website" varchar(200) NOT NULL
);
CREATE TABLE "books_book__new" (
"id" integer NOT NULL PRIMARY KEY AUTOINCREMENT,
"title" varchar(100) NOT NULL,
"publication_date" date NOT NULL,
"publisher_id" integer NOT NULL REFERENCES
"books_publisher" ("id")
);
INSERT INTO "books_book__new" ("id", "publisher_id", "title",
"publication_date") SELECT "id", NULL, "title", "publication_date" FROM
"books_book";
DROP TABLE "books_book";
ALTER TABLE "books_book__new" RENAME TO "books_book";
CREATE INDEX "books_book_2604cbea" ON "books_book" ("publisher_id");
COMMIT;
Django provides an easier way of committing the SQL to the database: the migrate command:
python manage.py migrate
then u'll see things like,
Operations to perform:
Apply all migrations: admin, auth, books, contenttypes, sessions
Running migrations:
Applying books.0001_initial... OK
