Django - Models Meta Options

According to the official document, the Meta class in a Django model is anything that is not a field. One example I provided was db_table, which allows you to decide the name of the table instead of using the default myapp_modelname.

Below are some examples;

1. abstract

If you set abstract=True, this model will be an abstract base class, which can be used as a model to inherit.

2. app_label

Can be used when the model is declared outside an app declared in INSTALLED_APPS in settings.py. However, I don’t see when I would use this.

3. db_tablespace

Default is DEFAULT_TABLESPACE setting in settings.py, which is an empty string, but you can change it according to your needs. I will write a post about talespace later.

4. default_related_name

The default value for this is <model_name>_set as in membership_set in the post where through relationship was declared. This option also sets the related_query_name.

5. get_latest_by

The name of a field or a list of field names in a model. This is usually DateField, DateTimeField, or IntegerField, which can be ordered numerically. This specifies the default fields to use in manager’s latest() and earliest() methods.

# Latest by ascending order_date.
get_latest_by = "order_date"

# Latest by priority descending, order_date ascending.
get_latest_by = ['-priority', 'order_date']

6. managed

The default is True, however, if set False, django does not perform any table creation or deletion operations in this model. This is useful when this model represents an existing table or a database view that has been created by some other means. I think this would come in handy when you are migrating a project build with PHP to Django.

7. order_with_respect_to

Declaring that you would like to order your jmodel with respect to aa field, ususally a ForeignKey like the example below;

from django.db import models

class Question(models.Model):
    text = models.TextField()
    # ...

class Answer(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    # ...

    class Meta:
        order_with_respect_to = 'question'

8. ordering

The default ordering for the example. Either a tuple or list of strings and?or query expressions. ordering = ['pub_date'], or ordering = ['-pub_date'] if you ant a descending order. You can also use query expressions like below;

ordering = [F('author').asc(nulls_last=True)]

You want to order it by a model called author in an ascending order while making null values sort last.