68 lines
1.9 KiB
Python
68 lines
1.9 KiB
Python
|
"""
|
||
|
|
Tests for the update() queryset method that allows in-place, multi-object
|
||
|
|
updates.
|
||
|
|
"""
|
||
|
|
|
||
|
|
from django.db import models
|
||
|
|
|
||
|
|
class DataPoint(models.Model):
|
||
|
|
name = models.CharField(max_length=20)
|
||
|
|
value = models.CharField(max_length=20)
|
||
|
|
another_value = models.CharField(max_length=20, blank=True)
|
||
|
|
|
||
|
|
def __unicode__(self):
|
||
|
|
return unicode(self.name)
|
||
|
|
|
||
|
|
class RelatedPoint(models.Model):
|
||
|
|
name = models.CharField(max_length=20)
|
||
|
|
data = models.ForeignKey(DataPoint)
|
||
|
|
|
||
|
|
def __unicode__(self):
|
||
|
|
return unicode(self.name)
|
||
|
|
|
||
|
|
|
||
|
|
__test__ = {'API_TESTS': """
|
||
|
|
>>> DataPoint(name="d0", value="apple").save()
|
||
|
|
>>> DataPoint(name="d2", value="banana").save()
|
||
|
|
>>> d3 = DataPoint(name="d3", value="banana")
|
||
|
|
>>> d3.save()
|
||
|
|
>>> RelatedPoint(name="r1", data=d3).save()
|
||
|
|
|
||
|
|
Objects are updated by first filtering the candidates into a queryset and then
|
||
|
|
calling the update() method. It executes immediately and returns nothing.
|
||
|
|
|
||
|
|
>>> DataPoint.objects.filter(value="apple").update(name="d1")
|
||
|
|
>>> DataPoint.objects.filter(value="apple")
|
||
|
|
[<DataPoint: d1>]
|
||
|
|
|
||
|
|
We can update multiple objects at once.
|
||
|
|
|
||
|
|
>>> DataPoint.objects.filter(value="banana").update(value="pineapple")
|
||
|
|
>>> DataPoint.objects.get(name="d2").value
|
||
|
|
u'pineapple'
|
||
|
|
|
||
|
|
Foreign key fields can also be updated, although you can only update the object
|
||
|
|
referred to, not anything inside the related object.
|
||
|
|
|
||
|
|
>>> d = DataPoint.objects.get(name="d1")
|
||
|
|
>>> RelatedPoint.objects.filter(name="r1").update(data=d)
|
||
|
|
>>> RelatedPoint.objects.filter(data__name="d1")
|
||
|
|
[<RelatedPoint: r1>]
|
||
|
|
|
||
|
|
Multiple fields can be updated at once
|
||
|
|
|
||
|
|
>>> DataPoint.objects.filter(value="pineapple").update(value="fruit", another_value="peaches")
|
||
|
|
>>> d = DataPoint.objects.get(name="d2")
|
||
|
|
>>> d.value, d.another_value
|
||
|
|
(u'fruit', u'peaches')
|
||
|
|
|
||
|
|
In the rare case you want to update every instance of a model, update() is also
|
||
|
|
a manager method.
|
||
|
|
|
||
|
|
>>> DataPoint.objects.update(value='thing')
|
||
|
|
>>> DataPoint.objects.values('value').distinct()
|
||
|
|
[{'value': u'thing'}]
|
||
|
|
|
||
|
|
"""
|
||
|
|
}
|