Field Storage API

  1. drupal
    1. 8
    2. 7

Implement a storage engine for Field API data.

The Field Attach API uses the Field Storage API to perform all "database access". Each Field Storage API hook function defines a primitive database operation such as read, write, or delete. The default field storage module, field_sql_storage.module, uses the local SQL database to implement these operations, but alternative field storage backends can choose to represent the data in SQL differently or use a completely different storage mechanism such as a cloud-based database.

Each field defines which storage backend it uses. The Drupal system variable 'field_storage_default' identifies the storage backend used by default.


FIELD_STORAGE_INSERTArgument for an insert operation.
FIELD_STORAGE_UPDATEArgument for an update operation.

Functions & methods

hook_field_display_alterAlters the display settings of a field before it gets displayed.
hook_field_display_ENTITY_TYPE_alterAlters the display settings of a field on a given entity type before it gets displayed.
hook_field_extra_fields_display_alterAlters the display settings of pseudo-fields before an entity is displayed.
hook_field_info_max_weightReturns the maximum weight for the entity components handled by the module.
hook_field_storage_create_fieldAct on creation of a new field.
hook_field_storage_deleteDelete all field data for an entity.
hook_field_storage_delete_fieldAct on deletion of a field.
hook_field_storage_delete_instanceAct on deletion of a field instance.
hook_field_storage_delete_revisionDelete a single revision of field data for an entity.
hook_field_storage_detailsReveal the internal details about the storage for a field.
hook_field_storage_details_alterPerform alterations on Field API storage details.
hook_field_storage_infoExpose Field API storage backends.
hook_field_storage_info_alterPerform alterations on Field API storage types.
hook_field_storage_loadLoad field data for a set of entities.
hook_field_storage_pre_insertAct before the storage backends insert field data.
hook_field_storage_pre_loadAct before the storage backends load field data.
hook_field_storage_pre_updateAct before the storage backends update field data.
hook_field_storage_queryExecute an EntityFieldQuery.
hook_field_storage_writeWrite field data for an entity.
hook_field_widget_properties_alterAlters the widget properties of a field instance before it gets displayed.
hook_field_widget_properties_ENTITY_TYPE_alterAlters the widget properties of a field instance on a given entity type before it gets displayed.

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