difference between values() and only()

Question

what's the difference between using:

Blabla.objects.values('field1', 'field2', 'field3') 

and

Blabla.objects.only('field1', 'field2', 'field3') 

Answer 1

Assuming Blabla has the fields in your question, as well as field4,

Blabla.objects.only('field1', 'field2', 'field3')[0].field4 

will return the value of that object's field4 (with a new database query to retrieve that info), whereas

Blabla.objects.values('field1', 'field2', 'field3')[0].field4 

will give

AttributeError: 'dict' object has no attribute 'field4' 

This is because .values() returns a QuerySet that returns dictionaries, which is essentially a list of dicts, rather than model instances (Blabla).