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83 lines
2.1 KiB
Python
83 lines
2.1 KiB
Python
"""
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Specifying ordering
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Specify default ordering for a model using the ``ordering`` attribute, which
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should be a list or tuple of field names. This tells Django how to order
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``QuerySet`` results.
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If a field name in ``ordering`` starts with a hyphen, that field will be
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ordered in descending order. Otherwise, it'll be ordered in ascending order.
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The special-case field name ``"?"`` specifies random order.
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The ordering attribute is not required. If you leave it off, ordering will be
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undefined -- not random, just undefined.
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"""
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from django.db import models
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class Author(models.Model):
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name = models.CharField(max_length=63, null=True, blank=True)
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editor = models.ForeignKey("self", models.CASCADE, null=True)
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class Meta:
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ordering = ("-pk",)
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class Article(models.Model):
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author = models.ForeignKey(Author, models.SET_NULL, null=True)
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second_author = models.ForeignKey(
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Author, models.SET_NULL, null=True, related_name="+"
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)
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headline = models.CharField(max_length=100)
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pub_date = models.DateTimeField()
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class Meta:
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ordering = (
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"-pub_date",
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models.F("headline"),
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models.F("author__name").asc(),
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models.OrderBy(models.F("second_author__name")),
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)
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class OrderedByAuthorArticle(Article):
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class Meta:
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proxy = True
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ordering = ("author", "second_author")
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class OrderedByFArticle(Article):
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class Meta:
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proxy = True
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ordering = (models.F("author").asc(nulls_first=True), "id")
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class ChildArticle(Article):
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pass
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class Reference(models.Model):
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article = models.ForeignKey(OrderedByAuthorArticle, models.CASCADE)
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class Meta:
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ordering = ("article",)
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class OrderedByExpression(models.Model):
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name = models.CharField(max_length=30)
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class Meta:
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ordering = [models.functions.Lower("name")]
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class OrderedByExpressionChild(models.Model):
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parent = models.ForeignKey(OrderedByExpression, models.CASCADE)
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class Meta:
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ordering = ["parent"]
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class OrderedByExpressionGrandChild(models.Model):
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parent = models.ForeignKey(OrderedByExpressionChild, models.CASCADE)
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