Most database designs can also provide a quick answer to questions of the form: “What information do I currently have right now about last week ?” However, historic questions like “What information did I have at the time last week about last week ?” are not often not as easy to answer. Using time as […]

E.F. (“Ted”) Codd conceived of his relational model for databases while working at IBM in 1969. Codd’s approach took a cue from first-order predicate logic, the basis of a large number of other mathematical systems, and was presented in terms of set theory leaving physical representation and access implementer-defined. In June of 1970, Codd laid […]