Connor RCH, Dearle A, Morrison R, Brown AL. Existentially Quantified Types as a Database Viewing Mechanism. In: Bancilhon F, Thanos C, Tsichritzis D (ed) Lecture Notes in Computer Science 416, Proc. 2nd International Conference on Extending Database Technology, Venice, Italy. Springer-Verlag, 1990, pp 301-315  Home/Search   Document Not in Database   Summary   Related Articles   Check

....can be statically type checked. Moreover, there is an algorithm to infer a principal type for any type consistent program involving views and classes. One issue we have not addressed in this paper is a proper treatment of persistent data, which require some form of dynamic typing. Connor et al. CDMB90] demonstrated that various features of views of persistent data can be represented by combining a form of localized dynamic typing and existential types. Their techniques seems to be complementary to our method. The rest of the paper is organized as follows. Section 2 defines the core language ....

R. Connor, A. Dearle, R. Morrison, and F. Brown. Existentially Quantified Types as a Database Viewing Mechanism. In Proc. International Conference on Extended Database Technologies, pp. 301--315, 1990.

....representations and intermediate program representations must be protected to avoid potential corruption of the persistent environment. Protection is only required when they are outside the control of the compiler. The required protection may be provided using the abstract data types of Napier88 [CDM 90] The compiler interface may be supported using the abstract data type shown in Figure 4.10. 70 rec type compilerPackage is abstype[ intermediateRep ] compiler : proc( sourceRep,table[ string,valueOrLocation ] result[ intermediateRep ] binder : proc( intermediateRep ,table[ ....

....val ) Figure 4.23 Unsafe interaction between abstract instances. A mechanism is required therefore to ensure that only operations and values from the same instance of an abstract type are mixed. It is desirable for this mechanism to operate statically. The abstract use clause of Napier88 [CDM 90] performs this function. Use of an abstract instance is restricted to a specified code section by the use clause. Consider the use clause of Figure 4.24. The use of intCounter is restricted to the block after the in which in this case is a single assignment operation. The compiler cannot detect ....

R.C.H. Connor, A. Dearle, R. Morrison and A.L. Brown "Existentially Quantified Types as a Database Viewing Mechanism" In Lecture Notes in Computer Science 416, SpringerVerlag (1990) pp 301-315.

....was originally planned as part of the PISA project [1] with the major goal of constructing a self contained, orthogonally persistent system. The system was also intended as, or turned out to be, a testbed for experiments in: type systems for data modelling [2 7] bulk data [8, 9] and protection [10, 11]; programming language implementation [12, 13] binding mechanisms [14 17] programming environments [17 20] system evolution [21 23] concurrency control and transactions [24 27] object stores [26, 28 35] and software engineering tools [36 39] The Napier88 system consists of the Napier88 ....

....in the interface with their abstracted type along with the procedures which manipulate them. Napier88 provides existentially quantified types (abstract data types) to implement 2nd order information hiding. To illustrate their utility, we will use the example of a banking system, taken from [10], in which customers have access to their accounts through autoteller machines. The autoteller machines have different 27 styles of access to accounts according to which bank the machine belongs. A customer s own bank may have full access to an account whereas another bank may not access the ....

Connor RCH, Dearle A, Morrison R, Brown AL. Existentially Quantified Types as a Database Viewing Mechanism. In: Bancilhon F, Thanos C, Tsichritzis D (ed) Lecture Notes in Computer Science 416, Proc. 2nd International Conference on Extending Database Technology, Venice, Italy. Springer-Verlag, 1990, pp 301-315

....Large bodies of data are inherently valuable, and must be protected against accidental or deliberate misuse. This is true in both persistent and non persistent programming systems. However, protection mechanisms in a persistent system may be modelled quite differently from a non persistent system [MBC90, CDM90]. As all data within a persistent system are subject to type system constraints, no unlawful access to the data may occur except in the event of system failure. This gives the property of type safety to permanent data, which can not be achieved in a non persistent system. A further effect of the ....

....quantified types over traditional 16 viewing mechanisms is that they are statically type checkable. The referential integrity provided by a persistent store ensures that views occur over the same instance of data, and the copying of data, with its associated integrity problems, is not necessary [CDM90]. 1.5.3 Typechecking across separately compiled modules Type equivalence checking is well understood within a program, but presents some extra problems in a persistent system which allows the independent compilation of co operating modules [CBC90] In a persistent system, data which is shared ....

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R.C.H. Connor, A. Dearle, R. Morrison and A.L. Brown "Existentially Quantified Types as a Database Viewing Mechanism" Proc. International Conference on Extending Database Technology, Fondazione Cini, Venice (March 1990) pp 301 170

....system. However, object modelling leaves some inherent problems unresolved. In this paper we address points 4 7 by identifying encapsulation as the offending concept. We develop an alternative to encapsulation which preserves information hiding, taken from our persistent programming experience [Connor et al. 1990], and show how the technique may be incorporated into systems using the O 2 OODBS. Thus this paper addresses only a very restricted case of the general problem of evolution in object based systems, that of monotonically increasing schema evolution. This is the case in which all changes to the ....

....use abstract data types to provide user views, allowing users to access parts of the raw data directly but with limited type information. This restricts the operations a user program may perform on the raw data, while retaining the ability to pass references to the raw data to interface procedures [Connor, et al. 1990]. For example, the database may implement a feature object as a structure and provide a procedure in a user view which creates a new feature object. That procedure returns to the user a reference to the structure implementing the object, with a restricted type. The user cannot discover the ....

Connor, R.C.H., Dearle, A., Morrison, R. and Brown, A.L. (1990) Existentially Quantified Types as a Database Viewing Mechanism. In F. Bancilhon, C. Thanos and D. Tsichritzis (ed) Lecture Notes in Computer Science 416. Springer-Verlag, pp. 301-315.

.... in the literature [Atkinson, 1978, Atkinson, et al. 1982, Atkinson et al. 1984, Atkinson et al. 1985, Atkinson and Morrison, 1985, Morrison et al. 1985, Morrison et al. 1986, Atkinson Buneman, 1987, Morrison et al. 1987, Atkinson et al. 1988b, Dearle Brown, 1988, Brown, 1989, Connor et al. 1990, Cooper, 1990a, Cooper, 1990b, Albano et al. 1993, Connor et al. 1993, Morrison et al. 1993, Morrison et al. 1995] They can be summarised as: improving programming productivity from simpler semantics; avoiding ad hoc arrangements for data translation and long term data storage; ....

....the controlled environment. Progress in these areas is discussed below. 3. 1 Types and Data Models The long term goal of research into persistent type systems is to unify type systems and data models by developing an adequate model of type that meets the computational needs of persistent systems [Connor, 1990]. Ideally we would like a simple set of types, and a type algebra, so that by a succession of operations and the provision of parameters, any data model or conceptual data model can be defined. This we have called the type alchemist s dream [Atkinson Morrison, 1986] Type systems provide both ....

[Article contains additional citation context not shown here]

Connor, R.C.H., Dearle, A., Morrison, R. & Brown, A.L., 1990. Existentially Quantified Types as a Database Viewing Mechanism. In Lecture Notes in Computer Science 416, Bancilhon, F., Thanos, C. & Tsichritzis, D. (ed.), Springer-Verlag, Proc. 2nd International Conference on Extending Database Technology, Venice, Italy pp 301-315.

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Connor, R.C.H., Dearle, A., Morrison, R. & Brown, A.L. "Existentially Quantified Types as a Database Viewing Mechanism". In Lecture Notes in Computer Science 416, Bancilhon, F., Thanos, C. & Tsichritzis, D. (ed), Springer-Verlag, Proc. 2nd International Conference on Extending Database Technology, Venice, Italy (1990) pp 301-315.

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* Connor, R.C.H., Dearle, A., Morrison, R. & Brown, A.L. "Existentially Quantified Types as a Database Viewing Mechanism". In Lecture Notes in Computer Science 416, Bancilhon, F., Thanos, C. & Tsichritzis, D. (ed), Springer-Verlag, Proc. 2nd International Conference on Extending Database Technology, Venice, Italy (1990) pp 301-315.

No context found.

Connor, R.C.H., Dearle, A., Morrison, R. & Brown, A.L. "Existentially Quantified Types as a Database Viewing Mechanism". In Lecture Notes in Computer Science 416, Bancilhon, F., Thanos, C. & Tsichritzis, D. (ed), Springer-Verlag (1990) pp 301-315.

No context found.

Connor, R.C.H., Dearle, A., Morrison, R. & Brown, A.L. "Existentially Quantified Types as a Database Viewing Mechanism". In Lecture Notes in Computer Science 416, Bancilhon, F., Thanos, C. & Tsichritzis, D. (ed), Springer-Verlag (1990) pp 301-315.

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