history - REsource history

The resource history maintains history entries for development resources. It allows preserving the state of a development object. Usually, the object state includes the instance state, state of base type instances and the state of instances owned by the resource object.

When creating history entries for subordinated owned resource instances, those will also get a history entry in their list.

When creating a history entry for a shared base type instance, derived instances are not maintained, but a history entry for the base type will be created, only. E.g. the history list for SDB_Type may contain history entries for SDB_Structure, SDB_Valuelist, ODC_ImpClass or ADK_Class.

In order to create a history entry, the context action CreateHistoryEntry() might be called, which copies the current object state to the history list. RestoreFromHistory() restores the state from the last history entry and removes the last history entry from the list. ClearHistory() removes all history entries. .