Method and system enabling a user to select a data element out of a set of available data elements through the use of a hierarchical view (e.g. a tree). Whenever the user needs to choose a data element, the system collects the descriptions of all data elements that are both available and relevant in accordance with the specific use from a set of available data elements through the use of a hierarchical view. The tree represents each entity (data element) as a node and the properties of each entity as sub-nodes under it, possibly grouped into property groups represented as tree nodes. The system hides all implementation aspects of the data structure from the user—selection of the required value causes the underlying system to automatically perform all required actions in order to retrieve, calculate or search for the desired data element.