An Algebra for the BiTemporal Nested Data Model

A generalized bitemporal relational data model (BTNM) is formalized for the representation of bitemporal data with nested structure of arbitrary depth. Time is represented by temporal elements. Time-varying attributes are timestamped by taking advantage of the nested feature of the model. Thus, the temporal dimension of the model is expressed by bitemporal nested attributes consisting of atomic time-varying attributes, a valid temporal attribute and a transaction temporal attribute. The advantages of tuple timestamping and attribute timestamping approaches are combined and their limitations are minimized since the temporal dimension is nested and not integral with the corresponding time-varying attribute. A novel recursive algebra for the proposed model is presented. All the operations are