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			30 lines
		
	
	
		
			679 B
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			30 lines
		
	
	
		
			679 B
		
	
	
	
		
			Python
		
	
	
	
	
	
| """
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| 16. Many-to-one relationships that can be null
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| 
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| To define a many-to-one relationship that can have a null foreign key, use
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| ``ForeignKey()`` with ``null=True`` .
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| """
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| 
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| from django.db import models
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| from django.utils.encoding import python_2_unicode_compatible
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| 
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| 
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| @python_2_unicode_compatible
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| class Reporter(models.Model):
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|     name = models.CharField(max_length=30)
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| 
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|     def __str__(self):
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|         return self.name
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| 
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| 
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| @python_2_unicode_compatible
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| class Article(models.Model):
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|     headline = models.CharField(max_length=100)
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|     reporter = models.ForeignKey(Reporter, null=True)
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| 
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|     class Meta:
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|         ordering = ('headline',)
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| 
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|     def __str__(self):
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|         return self.headline
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