Join operations in temporal databases

Joins are arguably the most important relational operators. Poor implementations are tantamount to computing the Cartesian product of the input relations. In a temporal database, the problem is more acute for two reasons. First, conventional techniques are designed for the evaluation of joins with equality predicates rather than the inequality predicates prevalentinvalid-timequeries.Second,thepresenceoftemporally varying data dramatically increases the size of a database. These factors indicate that specialized techniques are needed to efficiently evaluate temporal joins. We address this need for efficient join evaluation in temporal databases. Our purpose is twofold.We first survey all previously proposed temporal join operators. While many temporal join operators have been defined in previous work, this work has been done largely in isolation from competing proposals, with little, if any, comparison of the various operators. We then address evaluation algorithms, comparing the applic...

• Type: Conference
• Year: 2005
• Where: VLDB
• Authors: Dengfeng Gao, Christian S. Jensen, Richard T. Snodgrass, Michael D. Soo
• Keywords: Database, Temporal Database, Temporal Join Operators, Temporal Joins, VLDB 2005