mirror of
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178 lines
4.1 KiB
Python
178 lines
4.1 KiB
Python
"""
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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 decimal import Decimal
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from django.db import models
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class CategoryMetaDataManager(models.Manager):
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def get_by_natural_key(self, kind, name):
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return self.get(kind=kind, name=name)
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class CategoryMetaData(models.Model):
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kind = models.CharField(max_length=10)
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name = models.CharField(max_length=10)
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value = models.CharField(max_length=10)
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objects = CategoryMetaDataManager()
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class Meta:
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unique_together = (("kind", "name"),)
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def __str__(self):
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return "[%s:%s]=%s" % (self.kind, self.name, self.value)
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def natural_key(self):
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return (self.kind, self.name)
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class Category(models.Model):
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name = models.CharField(max_length=20)
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meta_data = models.ForeignKey(
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CategoryMetaData, models.SET_NULL, null=True, default=None
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)
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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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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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class TopicManager(models.Manager):
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def get_queryset(self):
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return super().get_queryset().select_related("category")
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class Topic(models.Model):
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name = models.CharField(max_length=255)
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category = models.ForeignKey(Category, models.CASCADE, null=True)
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objects = TopicManager()
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class Article(models.Model):
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author = models.ForeignKey(Author, models.CASCADE)
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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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meta_data = models.ManyToManyField(CategoryMetaData)
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topics = models.ManyToManyField(Topic)
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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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class AuthorProfile(models.Model):
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author = models.OneToOneField(Author, models.CASCADE, 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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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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class Movie(models.Model):
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actor = models.ForeignKey(Actor, models.CASCADE)
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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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class Team:
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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 str(self.title)
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class TeamField(models.CharField):
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def __init__(self):
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super().__init__(max_length=100)
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def get_db_prep_save(self, value, connection):
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return str(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 from_db_value(self, value, expression, connection):
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return Team(value)
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def value_to_string(self, obj):
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return self.value_from_object(obj).to_string()
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def deconstruct(self):
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name, path, args, kwargs = super().deconstruct()
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del kwargs["max_length"]
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return name, path, args, kwargs
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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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class BaseModel(models.Model):
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parent_data = models.IntegerField()
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class ProxyBaseModel(BaseModel):
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class Meta:
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proxy = True
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class ProxyProxyBaseModel(ProxyBaseModel):
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class Meta:
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proxy = True
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class ComplexModel(models.Model):
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field1 = models.CharField(max_length=10)
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field2 = models.CharField(max_length=10)
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field3 = models.CharField(max_length=10)
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