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SQL/TP: A temporal extension of SQL. (English) Zbl 0962.68052
Kuper, Gabriel (ed.) et al., Constraint databases. Berlin: Springer. 391-399 (2000).
Summary: Research in the area of temporal databases and query languages has produced a large number of proposals for temporal extensions of SQL; however, none of these proposals has been used in commercial database management systems nor become a basis for foundations of temporal database theory. The failure of these proposals can often be traced to overly complex syntax and unclear, ad hoc, and/or poorly defined semantic.
This chapter introduces a simple constraint-based approach to managing temporal data that leads to a sound model of temporal databases including a compact representation of temporal relations and a first-order complete query language backward compatible with standard SQL.
The proposed extension, SQL/TP, is a natural temporal extension of SQL. “TP” stands for Time Points, a new data type that we add to SQL to represent a universe of linearly ordered time instants. Consequently, techniques from previous chapters extended to handle duplicates, provide a meaningful semantics for queries and updates over a space-efficient (constraint) representation of temporal relations. In addition SQL/TP provides an efficient implementation path on top of existing relational systems based on compilation of temporal (constraint) queries to standard SQL queries over an explicitly chosen ground representation of constraints.
The chapter is organized as follows: Section 19.2 defines a temporal data model based on linear-order constraints, including a compact representation in computer storage. Section 19.3 introduces the syntax and semantics of SQL/TP and a compilation-based query evaluation technique, and concludes with a brief description of the implementation.
For the entire collection see [Zbl 0935.00022].
MSC:
68P15 Database theory
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