V. Breazu-Tannen, P. Buneman, and A. Ohori. Can object-oriented databases be statically typed? In Proc. 2 nd International Workshop on Database Programming Languages, pages 226 - 237, 1989. Morgan Kaufmann Publishers.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....type for the shading operation. Though parameterization greatly increases the amount of compile time type checking a compiler can perform, it also has its drawbacks. It is well known that mutable parameterized types cannot have internal structure without violating subtype compatibility rules [BTBO89] This leads to the undesirable property that if Student is a subtype of Person, Parallel Set[Student] cannot be a subtype of Parallel Set[Person] To understand this anomaly, consider the fragment of code in figure 3.3. Parallel Set[Y] is a subtype of Parallel Set[X] by virtue of Y being a ....

Val Breazu-Tannen, Peter Buneman, and Atsushi Ohori. Can Object-Oriented Databases be Statically Typed? In Second International Workshop on Database Programming Languages, Gleneden Beach, OR, June 1989.

....a No or Don t know . Free substitution by subtype instances does not necessarily give rise to the containment semantics, the instances of a subtype being those of its supertype or supertypes. This difference in semantics becomes important for determining function types For example (see [Breazu Tannen89]) what is the type for lx:Person.x 4.2. Typing in TEDM TEDM uses types to organize objects according to their structure. Objects of the same type have a similar structure, and we say that the objects conform to the type. In general, an object conforming to a type also conforms to its ....

Breazu-Tannen, V., Buneman, P. and Ohori, A., "Can Object-Oriented Databases Be Statically Typed?" Proceedings of the 2nd Workshop on Database nd fvNameN|="w n "| 191 Programming Languages. 1989.

....To maintain strict subtype compatibility, certain subtype relationships must be precluded. For example, if the type Student is a subtype of Person, strict subtype compatibility rules preclude Parallel Set[Student] from being a subtype of Parallel Set[Person] This anomaly is discussed in [BTBO89] in the context of O O database systems. The particular structure of Parallel Set must be investigated in more detail to determine how this restriction may be overcome. a) b) Shapes (c) Shapes (d) Figure 2: a) Three sets of pixels. b) Circle is shaded. c) Shapes contains the three sets. d) ....

Val Breazu-Tannen, Peter Buneman, and Atsushi Ohori. Can Object-Oriented Databases be Statically Typed? In Second International Workshop on Database Programming Languages, Gleneden Beach, OR, June 1989.

....shows an integration of method inheritance and a static type system with ML polymorphism. This approach is not subject to the phenomenon of loss of type information associated with type systems based on the subsumption rule [Car88] the problem observed by Cardelli and Wegner [CW85] see [BTBO89] for a discussion on this problem) However this approach relies on the structure of record types of objects: inheritance is derived from the polymorphic nature of eld selection. We would like to borrow from objectoriented languages the idea that the programmer can control the sharing of methods ....

V. Breazu-Tannen, P. Buneman, and A. Ohori. Can object-oriented databases be statically typed? In Proc. 2 nd International Workshop on Database Programming Languages, pages 226 - 237, 1989. Morgan Kaufmann Publishers.

....database values have unique types, while they have multiple types in Cardelli and Wegner s type systems. Database types in Machiavelli specify the exact structure of values and this property is needed in order to implement various database operations such as equality and natural join. See [BTBO89] for more discussion. Inheritance is thus achieved not by subtyping but by polymorphic instantiation of kinded type variables. The most important practical difference is that this polymorphism is inferred, which means that the programmer does not have to declare and explicitly instantiate the ....

V. Breazu-Tannen, P. Buneman, and A. Ohori. Can object-oriented databases be statically typed? In Proc. 2 nd International Workshop on Database Programming Languages, pages 226 -- 237, Gleneden Beach, Oregon, June 1989. Morgan Kaufmann Publishers. 46

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V. Breazu-Tannen, O.P. Buneman and A. Ohori "Can Object-Oriented Databases be Statically Typed?" In R. Hull, R. Morrison and D. Stemple (editors) Proc. 2nd International Workshop on Database Programming Languages Morgan - Kaufmann ( 1989 ) pp 226 - 237

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