# coding=utf-8from 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 relationshipsclass 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.nameclass 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=utf8class 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: admin@admin.com# 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 relationshipsclass 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 relationshipsclass 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