Codd's Recommendations for Date & Time Data Types and its implementations in ISO SQL, DB2, Oracle, and Transact-SQL

Abstract

Date and time data types are very important for business. From the point of view of the relational model of data, these data types are simply atomic domains - their structure and operations are unimportant. After the initial introduction of the relational model of data and the next following implementations based on that model, Codd, in Version 2 of the relational model of data, corrected his point of view introducing 14 recommendations about date and time data types. This paper investigates implementations of date and time data types in ISO SQL, DB2, Oracle and Transact-SQL.