A statistical interface for historical relational databases

A historical database is a vast source of data for statistical analysis. The paper presents a statistical interface for historical relational databases with an underlying data model which uses attribute time-stamping. The statistical interface we propose includes aggregate functions and transformations of data into tabular forms suitable for advanced statistical analysis and is capable of dealing with the subtle semantics of time and various issues associated with it. A new operation, called enumeration, is introduced into historical relational algebra. The enumeration operation derives a table of uniform data, for a set of specified time points or intervals, from a three dimensional historical relation. We also give a method for normalizing historical relations and aligning the time of their attributes.