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