Industry
While temporal databases has been an active research topic for over 20 years, in the last few years the insights and approaches from this research have been making their way into commercial products. These products provide support in various ways for transaction and valid time data.
This page offers links to commercial offerings that involve temporal database technology and that relate to temporal data management.
TIMEDB offers a temporal query language interface to valid-time, transaction-time, and bitemporal tables. TIMEDB translates temporal statements into SQL statements, which are then fed to an underlying standard DBMS. The temporal query language is temporally upward compatible with SQL. FlashBack queries in Oracle 9i: [an overview, by Surapaneni] [white paper]
FlashBack queries allow the application to access prior transaction-time states of their database; they are transaction timeslice queries. Database modifications and conventional queries are temporally upward compatible. FlashBack queries in Oracle 10g: [slides, by Bednar and Lubeck] [documentation]
Oracle 10g extends the flashback queries to retrieve all the versions of a row between two transaction times (a key-transaction-time-range query) and allows tables and databases to be rolled back to a previous transaction time, discarding all changes after that time. FlashBack Data Archive in Oracle 11g: [white paper, by Rajamani]
Oracle 11g introduces the Flashback Data Archive, which promises higher performance (in transaction processing and storage space), by storing logically-deleted records in the so-called Flashback Recovery Area. LogExplorer from Lumigent provides an analysis tool for Microsoft SQLServer logs, to allow one to view how rows change over time (a nonsequenced transaction-time query) and then to selectively back out and replay changes, on both relational data and the schema (it effectively treats the schema as a transaction-versioned schema). aTempo’s Time Navigator is a data replication tool for DB2, Oracle, Microsoft SQL Server and Sybase that extracts information from a database to build a slice repository, thereby enabling image-based restoration of a past slice; these are transaction time-slice queries. IBM’s DataPropagator can use data replication of a DB2 log to create both before and after images of every row modification to create a transaction-time database that can be later queried. MarkLogic Server stores XML documents as a transaction-time database and supports transaction timeslice queries in XQuery (termed “point-in-time queries”). Dydra, a graph database, supports native revisions, thus providing transaction-time support that enables retrieval according to transaction time.