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Python Django Basics Django Templates Ordering and 404s

Sahar Nasiri
Sahar Nasiri
7,454 Points
Posted by Sahar Nasiri
Sahar Nasiri
7,454 Points

Meta Class

I really don't understand why do we need this Meta class? I erased it and nothing has changed! I don't understand the use of this class when we do not make any instances of it.

1 Answer

Igor Yamshchykov
Igor Yamshchykov
24,397 Points
Igor Yamshchykov
Igor Yamshchykov
24,397 Points

Meta inner class in Django models: This is just a class container with some options (metadata) attached to the model. It defines such things as available permissions, associated database table name. For instance if you want to specify single or plural names for your model instances you will use Meta class for that. Or default ordering can be also specified there. So you don't need to create instances of this class by yourself, but your Django models will use it.

class Meta:
        verbose_name_plural = "products"

Like so.

You can also check out the explanation in Django docs, they have great clarification there https://docs.djangoproject.com/en/dev/topics/db/models/#meta-options

Hope that helps =)

Sahar Nasiri
Sahar Nasiri
7,454 Points
Sahar Nasiri
Sahar Nasiri
7,454 Points

Thanks, Igor :)). One question, I remember in Java, a class cannot be used unless you make an instance of that class, is it different here? Python uses inner classes anyway?

Sahar Nasiri
Sahar Nasiri
7,454 Points
Sahar Nasiri
Sahar Nasiri
7,454 Points

Something else, why does nothing change when I erase this Meta class? Is it because we have only one ordering?

Igor Yamshchykov
Igor Yamshchykov
24,397 Points
Igor Yamshchykov
Igor Yamshchykov
24,397 Points

Answering your question, I'm not sure how this works under the hood in Django, but I bet Django either creates an instance or has some mechanism for accessing properties that you've specify in Meta class. One remark to your note, you can access static methods and properties of the class even if you don't have an class instance I think this applies to Java as well. And yes, referring to the Django documentation Meta to a model is completely optional. So if you need to change some of those properties than you'll need to specify a Meta class, but I you don't change anything there, you can get rid of it.

Chris Freeman
Chris Freeman
Treehouse Moderator 68,454 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,454 Points

Another way to view the Meta class used in Django class definitions is as special instructions to the class constructor. These instructions provide ways to customize the inherited models.Model clsss.