Codd E.F. Relational Completeness of Database Sublanguages. Database Systems: Courant Computer Science Series Vol 6, Englewood Cliffs, New Jersey, Prentice Hall, 1972.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....simplicity with those expressed in conventional query languages. Efficiency techniques such as secondary indices and filter promotion can also be used. 3 Description of the Relational Calculus The relational calculus is a formalism for describing database queries which was first suggested by Codd [3] and underlies a number of query languages [2, 7, 13, 6] Essentially queries describe a desired set of tuples by specifying a predicate or formula the tuples must satisfy. This represents a declarative specification of the query and, unlike the relational algebra, no order needs to be given for ....

Codd E.F. Relational Completeness of Database Sublanguages. Database Systems: Courant Computer Science Series Vol 6, Englewood Cliffs, New Jersey, Prentice Hall, 1972.

....To illustrate the techniques, both the computational and non computational parts of Date s bill of material query are improved. 4. 1 Power Codd defined a query notation to be relationally complete, i.e. adequately expressive, if it is at least as powerful as the relational calculus [9]. The relational calculus and relational algebra have equivalent expressive power. The relational completeness of list comprehensions, augmented by three auxiliary functions, was proved by giving a translation that maps any relational calculus query into an equivalent list comprehension [24] The ....

Codd E.F. Relational Completeness of Database Sublanguages. Database Systems: Courant Computer Science Series Vol 6, Englewood Cliffs, New Jersey, Prentice Hall, 1972.

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