|
IBM System R
IBM System R is a database system built as a research project at IBM's San Jose Research Laboratory beginning in 1974. System R was a seminal project: it was the first implementation of SQL, which has since become the standard relational data query language. It was also the first system to demonstrate that a relational database management system could provide good transaction processing performance. Design decisions in System R, as well as some fundamental algorithm choices (such as the dynamic programming algorithm used in query optimization), influenced many later relational systems. System R's first customer was Pratt & Whitney in 1977.. See also * IBM Db2 * IBM SQL/DS * Ingres (database) * SQL * System/38 The System/38 is a discontinued minicomputer and midrange computer manufactured and sold by IBM. The system was announced in 1978. The System/38 has 48-bit addressing, which was unique for the time, and a novel integrated database system. It w ... References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relevance Logic
Relevance logic, also called relevant logic, is a kind of non-classical logic requiring the antecedent and consequent of implications to be relevantly related. They may be viewed as a family of substructural or modal logics. It is generally, but not universally, called ''relevant logic'' by British and, especially, Australian logicians, and ''relevance logic'' by American logicians. Relevance logic aims to capture aspects of implication that are ignored by the " material implication" operator in classical truth-functional logic, namely the notion of relevance between antecedent and conditional of a true implication. This idea is not new: C. I. Lewis was led to invent modal logic, and specifically strict implication, on the grounds that classical logic grants paradoxes of material implication such as the principle that a falsehood implies any proposition. Hence "if I'm a donkey, then two and two is four" is true when translated as a material implication, yet it seems intuitiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |