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"""
The lookup API
This demonstrates features of the database API.
"""
from django.db import models
from django.db.models.lookups import IsNull
class Alarm(models.Model):
desc = models.CharField(max_length=100)
time = models.TimeField()
def __str__(self):
return "%s (%s)" % (self.time, self.desc)
class Author(models.Model):
name = models.CharField(max_length=100)
alias = models.CharField(max_length=50, null=True, blank=True)
class Meta:
ordering = ("name",)
class Article(models.Model):
headline = models.CharField(max_length=100)
pub_date = models.DateTimeField()
author = models.ForeignKey(Author, models.SET_NULL, blank=True, null=True)
slug = models.SlugField(unique=True, blank=True, null=True)
class Meta:
ordering = ("-pub_date", "headline")
def __str__(self):
return self.headline
class Tag(models.Model):
articles = models.ManyToManyField(Article)
name = models.CharField(max_length=100)
class Meta:
ordering = ("name",)
class NulledTextField(models.TextField):
def get_prep_value(self, value):
return None if value == "" else value
class NullField(models.Field):
pass
NullField.register_lookup(IsNull)
@NulledTextField.register_lookup
class NulledTransform(models.Transform):
lookup_name = "nulled"
template = "NULL"
@property
def output_field(self):
return NullField()
@NulledTextField.register_lookup
class IsNullWithNoneAsRHS(IsNull):
lookup_name = "isnull_none_rhs"
can_use_none_as_rhs = True
class Season(models.Model):
year = models.PositiveSmallIntegerField()
gt = models.IntegerField(null=True, blank=True)
nulled_text_field = NulledTextField(null=True)
class Meta:
constraints = [
models.UniqueConstraint(fields=["year"], name="season_year_unique"),
]
def __str__(self):
return str(self.year)
class Game(models.Model):
season = models.ForeignKey(Season, models.CASCADE, related_name="games")
home = models.CharField(max_length=100)
away = models.CharField(max_length=100)
class Player(models.Model):
name = models.CharField(max_length=100)
games = models.ManyToManyField(Game, related_name="players")
class Product(models.Model):
name = models.CharField(max_length=80)
qty_target = models.DecimalField(max_digits=6, decimal_places=2)
class Stock(models.Model):
product = models.ForeignKey(Product, models.CASCADE)
short = models.BooleanField(default=False)
qty_available = models.DecimalField(max_digits=6, decimal_places=2)
class Freebie(models.Model):
gift_product = models.ForeignKey(Product, models.CASCADE)
stock_id = models.IntegerField(blank=True, null=True)
stock = models.ForeignObject(
Stock,
from_fields=["stock_id", "gift_product"],
to_fields=["id", "product"],
on_delete=models.CASCADE,
)
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