Nonsequenced semantics guarantees that query language statements can reference and manipulate the timestamps that capture the valid and transaction time of data in temporal databases as regular attribute values, with no built-in temporal semantics being enforced by the query language.
A temporal database generalizes a nontemporal database and associates one or more timestamps with database entities. Different authors have suggested temporal query languages that provide advanced support for formulating temporal statements. Results of these efforts include a variety of temporal extensions of SQL, temporal algebras, and temporal logics that simplify the management of temporal data.
Languages with built-in temporal support are attractive because they offer convenient support for formulating a wide range of common temporal statements. The classical example of advanced built-in temporal support is sequenced semantics, which makes it...
- 1.Abiteboul S, Herr L, Van den Bussche J. Temporal versus first-order logic to query temporal databases. In: Proceedings of the 15th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems; 1996. p. 49–57.Google Scholar