A VIEW assembles selected properties of one or more ENTITIEs into a separate named structure for read only use, usually to simplify an implementation. For example a CALL assembles POINT in JOURNEY PATTERN with PASSING TIMEs and other data describing a visit to an individual a STOP POINT by a SERVICE JOURNEY.  A view may have a persistent identity and version, but all its attributes are derived through existing relationship to other ENTITIES and its data values can be considered as copies of the normalised data from which is derived. <br/>