G. Ghelli, R. Orsini, A. Pereira Paz, and P.W. Trinder. Design of an Integrated Query and Manipulation Notation for Database Languages. Technical Report FIDE/92/41, University of Glasgow, U.K., 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....rules and the meaning of object comprehensions; it is not the way to implement object comprehensions efficiently. 4.1. 2 Other Extensions Implementations An extension to support local definitions in list comprehensions was suggested in [Ham90] Side effecting qualifiers were proposed in [GOPT92] They permit data to be manipulated by side effects in addition to being queried. The strong point is that such queries can still be optimised. The advantage of comprehensions over SQL, on which many objectoriented query languages are based, becomes clear when side effecting qualifiers are taken ....

....(continued) 4.3 Object Comprehensions The following subsections demonstrate object comprehensions using queries on the example database described in Section 2.13. Methods used in the examples are supposed to be without side effects. Side effecting methods can be dealt with as proposed in [GOPT92] The focus of each query is underlined. A discussion is given after each query. Queries involving staff members, students, and tutors should be read as staff members, students, and tutors of the Science Faculty, unless stated otherwise. 4.3.1 Support of Object Orientation Method Calling ....

G. Ghelli, R. Orsini, A. Pereira Paz, and P.W. Trinder. Design of an Integrated Query and Manipulation Notation for Database Languages. Technical Report FIDE/92/41, University of Glasgow, U.K., 1992.

.... shows that certain classes of bulk types can be treated consistently [Ohori, et al. 1989, Trinder Wadler, 1989, Breazu Tannen et al. 1991, Buneman et al. 1994] It has also been shown that these bulk types can be implemented by mapping them to the underlying system [Cooper and Qin, 1992, Ghelli et al. 1992, Matthes, 1992] If this target system has orthogonal persistence, then the bulk values inherit that persistence. It has long been argued that during this mapping, the traditional database optimisations can be accomplished [Cooper, et al. 1987] These optimisation techniques have yet to be ....

Ghelli, G., Orsini, R., Paz, A.P. & Trinder, P., 1992. Design of an Integrated Query and Manipulation Notation for Database Languages . ESPRIT BRA Project 3070 FIDE Technical Report FIDE/92/41.

....elements of the list A. More generally, a generator of the form P E contains a pattern P that binds one or more new variables to components of each element of the list. Queries List comprehensions easily express queries over relational [7, 24] functional [20, 22] and object oriented databases [11]. For concreteness let us consider the relational model, specifically a database with three relations used by Ullman [32] members (name, address, balance) orders (order no, oname, oitem, quantity) suppliers (sname, saddress, sitem, sprice) Let us assume that the underlying implementation ....

....the comprehension is executed. Hence it becomes the programmer s responsibility to ensure that the functions invoked are pure, i.e. side effect free, or that the side effects are well behaved. A systematic treatment of side effecting comprehensions in an object oriented language has been proposed [11]. 4 Power and Optimisation While query notations based on the relational algebra are easily optimised, they are not computationally complete neither computation nor recursion can be expressed. Conversely, queries expressed as procedures in a programming language can perform arbitrary ....

Ghelli G. Orsini R. Pereira Paz A. Trinder P.W. Design of an Integrated Query and Manipulation Notation for Database Languages. Submitted for publication.

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