# -*- coding: utf-8 -*- """ 42. Serialization ``django.core.serializers`` provides interfaces to converting Django ``QuerySet`` objects to and from "flat" data (i.e. strings). """ from __future__ import unicode_literals from decimal import Decimal from django.db import models from django.utils import six from django.utils.encoding import python_2_unicode_compatible @python_2_unicode_compatible class Category(models.Model): name = models.CharField(max_length=20) class Meta: ordering = ('name',) def __str__(self): return self.name @python_2_unicode_compatible class Author(models.Model): name = models.CharField(max_length=20) class Meta: ordering = ('name',) def __str__(self): return self.name @python_2_unicode_compatible class Article(models.Model): author = models.ForeignKey(Author) headline = models.CharField(max_length=50) pub_date = models.DateTimeField() categories = models.ManyToManyField(Category) class Meta: ordering = ('pub_date',) def __str__(self): return self.headline @python_2_unicode_compatible class AuthorProfile(models.Model): author = models.OneToOneField(Author, primary_key=True) date_of_birth = models.DateField() def __str__(self): return "Profile of %s" % self.author @python_2_unicode_compatible class Actor(models.Model): name = models.CharField(max_length=20, primary_key=True) class Meta: ordering = ('name',) def __str__(self): return self.name @python_2_unicode_compatible class Movie(models.Model): actor = models.ForeignKey(Actor) title = models.CharField(max_length=50) price = models.DecimalField(max_digits=6, decimal_places=2, default=Decimal('0.00')) class Meta: ordering = ('title',) def __str__(self): return self.title class Score(models.Model): score = models.FloatField() @python_2_unicode_compatible class Team(object): def __init__(self, title): self.title = title def __str__(self): raise NotImplementedError("Not so simple") def to_string(self): return "%s" % self.title class TeamField(models.CharField): def __init__(self): super(TeamField, self).__init__(max_length=100) def get_db_prep_save(self, value, connection): return six.text_type(value.title) def to_python(self, value): if isinstance(value, Team): return value return Team(value) def from_db_value(self, value, connection): return Team(value) def value_to_string(self, obj): return self._get_val_from_obj(obj).to_string() def deconstruct(self): name, path, args, kwargs = super(TeamField, self).deconstruct() del kwargs['max_length'] return name, path, args, kwargs @python_2_unicode_compatible class Player(models.Model): name = models.CharField(max_length=50) rank = models.IntegerField() team = TeamField() def __str__(self): return '%s (%d) playing for %s' % (self.name, self.rank, self.team.to_string())