Django db relationship

# coding=utf-8
from django.db import models

"""
Django数据库关系:
一对一关系:OneToOneField
多对多关系:ManyToManyField
多对一关系:ForeignKey
"""


## One-to-one relationships
class Place(models.Model):
    name = models.CharField(max_length=50)
    address = models.CharField(max_length=80)

    def __str__(self):              # __unicode__ on Python 2
        return "%s the place" % self.name

class Restaurant(models.Model):
    place = models.OneToOneField(Place, primary_key=True)
    serves_hot_dogs = models.BooleanField(default=False)
    serves_pizza = models.BooleanField(default=False)

    def __str__(self):              # __unicode__ on Python 2
        return "%s the restaurant" % self.place.name


## CREATE TABLE `db_place` (
##   `id` int(11) NOT NULL AUTO_INCREMENT,
##   `name` varchar(50) NOT NULL,
##   `address` varchar(80) NOT NULL,
##   PRIMARY KEY (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8
##
## CREATE TABLE `db_restaurant` (
##   `place_id` int(11) NOT NULL,
##   `serves_hot_dogs` tinyint(1) NOT NULL,
##   `serves_pizza` tinyint(1) NOT NULL,
##   PRIMARY KEY (`place_id`),
##   CONSTRAINT `db_restaurant_place_id_606d40e1_fk_db_place_id` FOREIGN KEY (`place_id`) REFERENCES `db_place` (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8


class Waiter(models.Model):
    restaurant = models.ForeignKey(Restaurant)
    name = models.CharField(max_length=50)

    def __str__(self):              # __unicode__ on Python 2
        return "%s the waiter at %s" % (self.name, self.restaurant)

# CREATE TABLE `db_waiter` (
#   `id` int(11) NOT NULL AUTO_INCREMENT,
#   `name` varchar(50) NOT NULL,
#   `restaurant_id` int(11) NOT NULL,
#   PRIMARY KEY (`id`),
#   KEY `db_waiter_ee9d9d3e` (`restaurant_id`),
#   CONSTRAINT `db_waiter_restaurant_id_7b6c7331_fk_db_restaurant_place_id` FOREIGN KEY (`restaurant_id`) REFERENCES `db_restaurant` (`place_id`)
# ) ENGINE=InnoDB DEFAULT CHARSET=utf8
#
# >python manage.py syncdb
# Operations to perform:
#   Apply all migrations: admin, contenttypes, auth, sessions
# Running migrations:
#   Applying contenttypes.0001_initial... OK
#   Applying auth.0001_initial... OK
#   Applying admin.0001_initial... OK
#   Applying sessions.0001_initial... OK
#
# You have installed Django‘s auth system, and don‘t have any superusers defined.
# Would you like to create one now? (yes/no): yes
# Username (leave blank to use ‘zhangsan‘): admin
# Email address: [email protected]
# Password:*****
# Password (again):*****
# Superuser created successfully.
#
# >python manage.py makemigrations
# Migrations for ‘db‘:
#   0001_initial.py:
#     - Create model Place
#     - Create model Restaurant
#     - Create model Waiter
#
# >python manage.py migrate
# Operations to perform:
#   Apply all migrations: admin, contenttypes, db, auth, sessions
# Running migrations:
#   Applying db.0001_initial... OK



## Many-to-many relationships
class Publication(models.Model):
    title = models.CharField(max_length=30)

    def __str__(self):              # __unicode__ on Python 2
        return self.title

    class Meta:
        ordering = (‘title‘,)

class Article(models.Model):
    headline = models.CharField(max_length=100)
    publications = models.ManyToManyField(Publication)

    def __str__(self):              # __unicode__ on Python 2
        return self.headline

    class Meta:
        ordering = (‘headline‘,)

## CREATE TABLE `db_publication` (
##   `id` int(11) NOT NULL AUTO_INCREMENT,
##   `title` varchar(30) NOT NULL,
##   PRIMARY KEY (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8
##
##
## CREATE TABLE `db_article` (
##   `id` int(11) NOT NULL AUTO_INCREMENT,
##   `headline` varchar(100) NOT NULL,
##   PRIMARY KEY (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8
##
## CREATE TABLE `db_article_publications` (
##   `id` int(11) NOT NULL AUTO_INCREMENT,
##   `article_id` int(11) NOT NULL,
##   `publication_id` int(11) NOT NULL,
##   PRIMARY KEY (`id`),
##   UNIQUE KEY `article_id` (`article_id`,`publication_id`),
##   KEY `db_article_publications_a00c1b00` (`article_id`),
##   KEY `db_article_publications_72ef6487` (`publication_id`),
##   CONSTRAINT `db_article_publicat_publication_id_407fcd4d_fk_db_publication_id` FOREIGN KEY (`publication_id`) REFERENCES `db_publication` (`id`),
##   CONSTRAINT `db_article_publications_article_id_b757f51_fk_db_article_id` FOREIGN KEY (`article_id`) REFERENCES `db_article` (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8

# >python manage.py makemigrations
# Migrations for ‘db‘:
#   0002_auto_20141013_1311.py:
#     - Create model Article
#     - Create model Publication
#     - Add field publications to article
#
# >python manage.py migrate
# Operations to perform:
#   Apply all migrations: admin, contenttypes, db, auth, sessions
# Running migrations:
#   Applying db.0002_auto_20141013_1311... OK


## Many-to-one relationships
class Reporter(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)
    email = models.EmailField()

    def __str__(self):              # __unicode__ on Python 2
        return "%s %s" % (self.first_name, self.last_name)

class Articler(models.Model):
    headline = models.CharField(max_length=100)
    pub_date = models.DateField()
    reporter = models.ForeignKey(Reporter)

    def __str__(self):              # __unicode__ on Python 2
        return self.headline

    class Meta:
        ordering = (‘headline‘,)

## CREATE TABLE `db_reporter` (
##   `id` int(11) NOT NULL AUTO_INCREMENT,
##   `first_name` varchar(30) NOT NULL,
##   `last_name` varchar(30) NOT NULL,
##   `email` varchar(75) NOT NULL,
##   PRIMARY KEY (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8
## 
## CREATE TABLE `db_articler` (
##   `id` int(11) NOT NULL AUTO_INCREMENT,
##   `headline` varchar(100) NOT NULL,
##   `pub_date` date NOT NULL,
##   `reporter_id` int(11) NOT NULL,
##   PRIMARY KEY (`id`),
##   KEY `db_articler_947bdf92` (`reporter_id`),
##   CONSTRAINT `db_articler_reporter_id_26a49a33_fk_db_reporter_id` FOREIGN KEY (`reporter_id`) REFERENCES `db_reporter` (`id`)
## ) ENGINE=InnoDB DEFAULT CHARSET=utf8

# >python manage.py makemigrations
# Migrations for ‘db‘:
#   0003_auto_20141013_1318.py:
#     - Create model Articler
#     - Create model Reporter
#     - Add field reporter to articler
#
# >python manage.py migrate
# Operations to perform:
#   Apply all migrations: admin, contenttypes, db, auth, sessions
# Running migrations:
#   Applying db.0003_auto_20141013_1318... OK