怎么在Django框架中获取单个对象数据？

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数据分析师 · Answer

How to get single object data in the Django framework? -PHP Chinese website Q&A-How to obtain single object data in the Django framework? -PHP Chinese website Q&A

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伊谢尔伦 · Answer

相对列表来说，有些时候我们更需要获取单个的对象， `` get()`` 方法就是在此时使用的：

>>> Publisher.objects.get(name="Apress")

这样，就返回了单个对象，而不是列表（更准确的说，QuerySet)。所以，如果结果是多个对象，会导致抛出异常：

>>> Publisher.objects.get(country="U.S.A.")
Traceback (most recent call last):
  ...
MultipleObjectsReturned: get() returned more than one Publisher --
  it returned 2! Lookup parameters were {'country': 'U.S.A.'}

如果查询没有返回结果也会抛出异常：

>>> Publisher.objects.get(name="Penguin")
Traceback (most recent call last):
  ...
DoesNotExist: Publisher matching query does not exist.

这个 DoesNotExist 异常是 Publisher 这个 model 类的一个属性，即 Publisher.DoesNotExist。在你的应用中，你可以捕获并处理这个异常，像这样：

try:
  p = Publisher.objects.get(name='Apress')
except Publisher.DoesNotExist:
  print "Apress isn't in the database yet."
else:
  print "Apress is in the database."

怎么在Django框架中获取单个对象数据？

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