django我们可以在预取相关模型中选择相关的字段吗? [英] django can we select related a field on a prefetch related model?
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问题描述
class A():
a = manytomany('B')
class B():
b = charfield()
z = foreignkey('C')
class C():
c = charfield()
也可以这样做来获取 z
:
foo = A .objects.get(pk = 1).prefetch_related('a')。select_related('a__z')
解决方案
您只需要一个 prefetch_related
call:
foo = A.objects.prefetch_related('a__z')。get(pk = 1)
这将预取两个表。
Assuming these as django model for the sake of simplcity:
class A():
a = manytomany('B')
class B():
b = charfield()
z = foreignkey('C')
class C():
c = charfield()
Can we do something like this to fetch the z
also:
foo = A.objects.get(pk = 1).prefetch_related('a').select_related('a__z')
解决方案
You only need one prefetch_related
call:
foo = A.objects.prefetch_related('a__z').get(pk=1)
This will prefetch both tables.
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