mirror of
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8dde0504f3
CAST() must be wrapped in parentheses to be recognized as an expression on SQLite. Regression in 7414704e88d73dafbcfbb85f9bc54cb6111439d3. Backport of 797957fb48f63760442d3d4c8985fd94f8602d5e from main
71 lines
2.2 KiB
Python
71 lines
2.2 KiB
Python
"""
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Callable defaults
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You can pass callable objects as the ``default`` parameter to a field. When
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the object is created without an explicit value passed in, Django will call
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the method to determine the default value.
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This example uses ``datetime.datetime.now`` as the default for the ``pub_date``
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field.
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"""
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from datetime import datetime
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from decimal import Decimal
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from django.db import models
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from django.db.models.functions import Coalesce, ExtractYear, Now, Pi
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from django.db.models.lookups import GreaterThan
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class Article(models.Model):
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headline = models.CharField(max_length=100, default="Default headline")
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pub_date = models.DateTimeField(default=datetime.now)
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def __str__(self):
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return self.headline
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class DBArticle(models.Model):
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"""
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Values or expressions can be passed as the db_default parameter to a field.
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When the object is created without an explicit value passed in, the
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database will insert the default value automatically.
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"""
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headline = models.CharField(max_length=100, db_default="Default headline")
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pub_date = models.DateTimeField(db_default=Now())
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cost = models.DecimalField(
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max_digits=3, decimal_places=2, db_default=Decimal("3.33")
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)
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class Meta:
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required_db_features = {"supports_expression_defaults"}
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class DBDefaults(models.Model):
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both = models.IntegerField(default=1, db_default=2)
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null = models.FloatField(null=True, db_default=1.1)
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class DBDefaultsFunction(models.Model):
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number = models.FloatField(db_default=Pi())
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year = models.IntegerField(db_default=ExtractYear(Now()))
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added = models.FloatField(db_default=Pi() + 4.5)
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multiple_subfunctions = models.FloatField(db_default=Coalesce(4.5, Pi()))
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case_when = models.IntegerField(
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db_default=models.Case(models.When(GreaterThan(2, 1), then=3), default=4)
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)
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class Meta:
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required_db_features = {"supports_expression_defaults"}
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class DBDefaultsPK(models.Model):
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language_code = models.CharField(primary_key=True, max_length=2, db_default="en")
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class DBDefaultsFK(models.Model):
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language_code = models.ForeignKey(
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DBDefaultsPK, db_default="fr", on_delete=models.CASCADE
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)
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