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797957fb48
CAST() must be wrapped in parentheses to be recognized as an expression on SQLite.
Regression in 7414704e88.
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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