Locking, Interlocking, and Blocking of Entities
To control the concurrent access to data, MDG uses the following concepts:
Locking of Objects
The system prevents simultaneous access from different logical units of work (LUWs) to the same object by locking the object. This ensures, that at a single point in time an object is processed by only one user. When you edit any part of an object, the system automatically locks the complete object. As a consequence, you cannot work on more than one parallel change requests for the same object at the same time, even if it is a change request of a parallel change request type.
Interlocking of Entities
The system ensures that there is not more than one open change request assigned to an entity by interlocking an entity with an open change request. If you use a non-parallel change request to process an object, all its entities are interlocked by this change request using the object list.
In parallel change requests the object list only registers the processed object but does not interlock it. Interlocking is done on entity level by creating, changing or deleting entities of a business object. For this purpose the change list has been introduced for interlocking entities of business objects. The change list contains the entities that are changed with a change request. For each parallel change request you need to configure the scope on entity type level to define which parts of a business object can potentially be edited with a certain change request type. However, an entity is only interlocked with a change request as soon as it is changed or created.
NoteA change in one entity may result in a cross derivation of another entity of a different entity type. Since the change request must then also interlock the derived entity, both entity types need to be part of the change request scope.
End of the note.For more information, see Parallel Change Requests.
Blocking of Entities
The system prevents that an entity is changed that must not be changed due to application specific reasons by blocking an entity. With the MDG application framework you can block entities to ensure that these entities are not added to change requests. The system checks, if application specific reasons exist, whenever an entity is added to the object list of a change request.
Because the blocking reason is provided by the access class, only entities with a reuse active area can be blocked or can be used to create blocks for other entities
For more information, see Blocking of Entities (Block List).