db.models.Field.from_db_value()

from_db_value(value, expression, connection, context)

Converts a value as returned by the database to a Python object. It is the reverse of get_prep_value().

This method is not used for most built-in fields as the database backend already returns the correct Python type, or the backend itself does the conversion.

See Converting values to Python objects for usage.

Note

For performance reasons, from_db_value is not implemented as a no-op on fields which do not require it (all Django fields). Consequently you may not call super in your definition.

When saving, pre_save() and get_db_prep_save() are used:

Links:

https://docs.djangoproject.com/en/1.10/ref/models/fields/#django.db.models.Field.from_db_value

doc_Django

2016-10-09 18:35:25

Comments

Popular Articles

db.models.Field class Field [source] Field is an abstract class that represents a database table column. Django uses fields to create the database table (db_type(

db.models.Field.model Field.model Returns the model on which the field is defined. If a field is defined on a superclass of a model, model will refer to the superclass,

db.models.Field.null Field.null If True, Django will store empty values as NULL in the database. Default is False. Avoid using null on string-based fields such as Char

db.models.Field.editable Field.editable If False, the field will not be displayed in the admin or any other ModelForm. They are also skipped during model validation. Defau

db.models.Field.description description A verbose description of the field, e.g. for the django.contrib.admindocs application. The description can be of the form: description