CTX_Structure :: GetOldInstance - Get old instance
The function returns the "old instance" state as it is stored still in the database. This allows comparing old and new values within the DBModify() or DBStore() handler.
Return value: Instance area ( ::Instance )
Instances do have the type of the referenced property handle (collection type). The instance contains a pointer to a properly structured instance area.
You can use the !-operator or the GetData() function to check whether the instance refers to data or not.