In Database Query Languages
Further information: Hierarchical and recursive queries in SQLSince the 1980s Oracle Database has implemented a proprietary SQL extension CONNECT BY... START WITH that allows the computation of a transitive closure as part of a declarative query. The SQL 3 (1999) standard added a more general WITH RECURSIVE construct also allowing transitive closures to be computed inside the query processor; as of 2011 the latter is implemented in IBM DB2, Microsoft SQL Server, and PostgreSQL, although not in MySQL (Benedikt and Senellart 2011:189).
Datalog also implements transitive closure computations (Silberschatz et al. 2010:C.3.6).
Read more about this topic: Transitive Closure
Famous quotes containing the words query and/or languages:
“Such condition of suspended judgment indeed, in its more genial development and under felicitous culture, is but the expectation, the receptivity, of the faithful scholar, determined not to foreclose what is still a question—the “philosophic temper,” in short, for which a survival of query will be still the salt of truth, even in the most absolutely ascertained knowledge.”
—Walter Pater (1839–1894)
“The very natural tendency to use terms derived from traditional grammar like verb, noun, adjective, passive voice, in describing languages outside of Indo-European is fraught with grave possibilities of misunderstanding.”
—Benjamin Lee Whorf (1897–1934)