Field Storage API

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 Backdrop system variable 'field_storage_default' identifies the storage backend used by default.

See Field API for information about the other parts of the Field API.

File

core/modules/field/field.attach.inc, line 7

Field attach API, allowing entities (nodes, users, ...) to be 'fieldable'.

Functions

Name	Location	Description
hook_field_storage_create_field	core/modules/field/field.api.php	Act on creation of a new field.
hook_field_storage_delete	core/modules/field/field.api.php	Delete all field data for an entity.
hook_field_storage_delete_field	core/modules/field/field.api.php	Act on deletion of a field.
hook_field_storage_delete_instance	core/modules/field/field.api.php	Act on deletion of a field instance.
hook_field_storage_delete_revision	core/modules/field/field.api.php	Delete a single revision of field data for an entity.
hook_field_storage_details	core/modules/field/field.api.php	Reveal the internal details about the storage for a field.
hook_field_storage_details_alter	core/modules/field/field.api.php	Perform alterations on Field API storage details.
hook_field_storage_info	core/modules/field/field.api.php	Expose Field API storage backends.
hook_field_storage_info_alter	core/modules/field/field.api.php	Perform alterations on Field API storage types.
hook_field_storage_load	core/modules/field/field.api.php	Load field data for a set of entities.
hook_field_storage_pre_insert	core/modules/field/field.api.php	Act before the storage backends insert field data.
hook_field_storage_pre_load	core/modules/field/field.api.php	Act before the storage backends load field data.
hook_field_storage_pre_update	core/modules/field/field.api.php	Act before the storage backends update field data.
hook_field_storage_purge	core/modules/field/field.api.php	Remove field storage information when field data is purged.
hook_field_storage_purge_field	core/modules/field/field.api.php	Remove field storage information when a field record is purged.
hook_field_storage_purge_field_instance	core/modules/field/field.api.php	Remove field storage information when a field instance is purged.
hook_field_storage_query	core/modules/field/field.api.php	Execute an EntityFieldQuery.
hook_field_storage_write	core/modules/field/field.api.php	Write field data for an entity.

Constants

Name	Location	Description
FIELD_STORAGE_INSERT	core/modules/field/field.attach.inc	Argument for an insert operation.
FIELD_STORAGE_UPDATE	core/modules/field/field.attach.inc	Argument for an update operation.