django how to create models

models.py

from __future__ import unicode_literals

from django.db import models

# Create your models here.

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)

class Author(models.Model):

salutation = models.CharField(max_length=10)

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()

settings.py

INSTALLED_APPS = [

    'django.contrib.admin',

    'django.contrib.auth',

    'django.contrib.contenttypes',

    'django.contrib.sessions',

    'django.contrib.messages',

    'django.contrib.staticfiles',

    'example',

'books'

my app name is book

                                                    Microsoft Windows [Version 6.1.7601]

Copyright (c) 2009 Microsoft Corporation.  All rights reserved.                                                                                                                  

C:\Users\hariz>cd mysite

C:\Users\hariz\mysite>manage.py startapp books

C:\Users\hariz\mysite>manage.py makemigrations

Migrations for 'books':

  books\migrations\0001_initial.py:

    - Create model Author

    - Create model Book

    - Create model Publisher

    - Add field publisher to book

C:\Users\hariz\mysite>manage.py makemigrations --name books

No changes detected

C:\Users\hariz\mysite>python manage.py showmigrations books

books

 [X] 0001_initial

C:\Users\hariz\mysite>python manage.py sqlmigrate books 0001_initial

BEGIN;

--

-- Create model Author

--

CREATE TABLE `books_author` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `

salutation` varchar(10) NOT NULL, `first_name` varchar(30) NOT NULL, `last_name`

 varchar(40) NOT NULL, `email` varchar(254) NOT NULL);

--

-- Create model Book

--

CREATE TABLE `books_book` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `ti

tle` varchar(100) NOT NULL, `publication_date` date NOT NULL);

CREATE TABLE `books_book_authors` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY

KEY, `book_id` integer NOT NULL, `author_id` integer NOT NULL);

--

-- Create model Publisher

--

CREATE TABLE `books_publisher` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY

, `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 NUL

L, `website` varchar(200) NOT NULL);

--

-- Add field publisher to book

--

ALTER TABLE `books_book` ADD COLUMN `publisher_id` integer NOT NULL;

ALTER TABLE `books_book` ALTER COLUMN `publisher_id` DROP DEFAULT;

ALTER TABLE `books_book_authors` ADD CONSTRAINT `books_book_authors_book_id_ed34

33e7_fk_books_book_id` FOREIGN KEY (`book_id`) REFERENCES `books_book` (`id`);

ALTER TABLE `books_book_authors` ADD CONSTRAINT `books_book_authors_author_id_98

4f1ab8_fk_books_author_id` FOREIGN KEY (`author_id`) REFERENCES `books_author` (

`id`);

ALTER TABLE `books_book_authors` ADD CONSTRAINT `books_book_authors_book_id_8714

badb_uniq` UNIQUE (`book_id`, `author_id`);

ALTER TABLE `books_book` ADD CONSTRAINT `books_book_publisher_id_189e6c56_fk_boo

ks_publisher_id` FOREIGN KEY (`publisher_id`) REFERENCES `books_publisher` (`id`

);

COMMIT;

C:\Users\hariz\mysite>manage.py shell

Python 2.7.11 (v2.7.11:6d1b6a68f775, Dec  5 2015, 20:32:19) [MSC v.1500 32 bit (

Intel)] on win32

Type "help", "copyright", "credits" or "license" for more information.

(InteractiveConsole)

> from books.models import Publisher

>>> newPublisher=Publisher(name='hari',address='trichy',city='trichy',state_prov

ince='tamilnadu',country='india')

>>> newPublisher.save

<bound method Publisher.save of <Publisher: Publisher object>>

>>> newPublisher.name='guru'

>>> newPublisher.save()

>>> new1Publisher=Publisher.objects.get(id=1)

>>> new1Publisher.name

u'Apress'

>>> new1Publisher=Publisher.objects.get(id=3)

>>> new1Publisher.name

u'guru'