Django检查字段是否为空白？ [英] Django check to see if field is blank?

问题描述

我从数据库中检索到一个对象。该对象具有外键字段，属性为空白= True。如何查看是否实际留空？

感谢您的帮助！

解决方案

blank = True 只是告诉管理员网站，该字段可以留空。

除非您设置 null = True ，否则您的数据库应该投诉，如果您尝试输入一个空白值。

如果您的外键字段可以取空值，它将返回None，否则为空，以检查是否为空白，您只需检查该字段是否为无。

 >>> obj.foreignkeyfield是无
 True 
 
 
如果没有obj.foreignkeyfield：
 print该字段留空
  

I retrieved an object from my database. This object has a foreign key field, with the attribute blank=True. How can I check to see if it was actually left blank?

Thanks for the help!

解决方案

blank=True is just telling the admin site that the field can be left blank.

Unless you set null=True as well, your database should complain if you tried to enter a blank value.

If your foreign key field can take null values, it will return None on null, so to check if it was "left blank", you could simply check if the field is None.

>>>   obj.foreignkeyfield is None
True


if not obj.foreignkeyfield:
    print "This field was left blank"

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