Field.auto_created Boolean flag that indicates if the field was automatically created, such as the OneToOneField

Field.null If True, Django will store empty values as NULL in the database. Default is False

ImageField.height_field Name of a model field which will be auto-populated with the height of the image each time the model

ForeignKey.swappable Controls the migration framework’s reaction if this ForeignKey is pointing at a swappable

CASCADE [source] Cascade deletes. Django emulates the behavior of the SQL constraint ON DELETE

SET_NULL [source] Set the ForeignKey null; this is only possible if null

Field.editable If False, the field will not be displayed in the admin or any other

Field.unique_for_month Like unique_for_date, but requires the field to be unique with respect to the month.

ImageField.width_field Name of a model field which will be auto-populated with the width of the image each time the model instance

DateField.auto_now_add Automatically set the field to now when the object is first created. Useful for creation of timestamps