Field API

Attaches custom data fields to Drupal entities.

The Field API allows custom data fields to be attached to Drupal entities and takes care of storing, loading, editing, and rendering field data. Any entity type (node, user, etc.) can use the Field API to make itself "fieldable" and thus allow fields to be attached to it. Other modules can provide a user interface for managing custom fields via a web browser as well as a wide and flexible variety of data type, form element, and display format capabilities.

The Field API defines two primary data structures, FieldStorage and Field, and the concept of a Bundle. A FieldStorage defines a particular type of data that can be attached to entities. A Field is attached to a single Bundle. A Bundle is a set of fields that are treated as a group by the Field Attach API and is related to a single fieldable entity type.

For example, suppose a site administrator wants Article nodes to have a subtitle and photo. Using the Field API or Field UI module, the administrator creates a field named 'subtitle' of type 'text' and a field named 'photo' of type 'image'. The administrator (again, via a UI) creates two Field Instances, one attaching the field 'subtitle' to the 'node' bundle 'article' and one attaching the field 'photo' to the 'node' bundle 'article'. When the node storage loads an Article node, it loads the values of the 'subtitle' and 'photo' fields because they are both attached to the 'node' bundle 'article'.

• Field Types API: Defines field types, widget types, and display formatters. Field modules use this API to provide field types like Text and Node Reference along with the associated form elements and display formatters.

• Field API bulk data deletion: Cleans up after bulk deletion operations such as deletion of field storage or field.

File

core/modules/field/field.module, line 27

Attach custom data fields to Drupal entities.

Functions