Reddi, S. (1993) Integrity Constraint Enforcement in the Functional Database Language PFL, in Proceedings of the 11th British National Conference on Databases, Worboys, M. and Grundy, A.F. (eds.), Keele, U.K. Springer-Verlag, 238--257.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....comparatively easy for most systems. In fact, in some systems which are based upon a declarative paradigm themselves, constraints are expressed directly as queries, usually with the implied restriction that they will evaluate to the empty set if the database integrity is not violated (Erwig 1991, Reddi 1993). However, having to check the entire database for validity is not an e#cient way to check integrity, especially if the query has to be executed after every update operation. One of the most significant contributions to this problem, which has since been used as the basis for almost all ....

Reddi, S. (1993) Integrity Constraint Enforcement in the Functional Database Language PFL, in Proceedings of the 11th British National Conference on Databases, Worboys, M. and Grundy, A.F. (eds.), Keele, U.K. Springer-Verlag, 238--257.

....is comparatively easy for most systems. In fact, in some systems which are based upon a declarative paradigm themselves, constraints are expressed directly as queries, usually with the implied restriction that they will evaluate to the empty set if the database integrity is not violated [11, 26]. However, having to check the entire database for validity is not an efficient way to check integrity, especially if the query has to be executed after every update operation. One of the most significant contributions to this problem, which has since been used as the basis for almost all ....

S. Reddi. Integrity Constraint Enforcement in the Functional Database Language PFL. In M. Worboys and A.F. Grundy, editors, Proceedings of the 11th British National Conference on Databases, pages 238--257, Keele, U.K., July 1993. Springer-Verlag.

....improved. In Section 3, we consider the need for improved user communication in transaction repair systems, and describe our own approach. Section 4 concludes. 2 Reporting Constraint Violations Despite the many proposals for integrity checking mechanisms proposed in the database literature (e.g. [24, 3, 15, 22, 7]) remarkably little has been said about the problems of reporting constraint violation to the user. Most of the proposals ignore the question completely; at best some authors [4] suggest retaining the declarative specification of the constraint in some form so that it can be displayed to the user ....

S. Reddi. Integrity Constraint Enforcement in the Functional Database Language PFL. In M. Worboys and A.F. Grundy, editors, Proceedings of the 11th British National Conference on Databases, pages 238--257, Keele, U.K., July 1993. Springer-Verlag.

....constraints can express cardinality and other aggregation constraints. For example, twoParents ensures that anyone who is recorded as having parents has precisely two parents: constraint twoParents = fx j (y; x) parents; count fy j (y; z) parents; z = xg) 2g We refer the reader to [Red93, Pou93] for a discussion of how integrity constraints can be automatically, and incrementally, enforced in the face of updates to the underlying data functions. 3 The Database Integration Strategy In this section we first formally define the notion of a component database in section 3.1. We then ....

S. Reddi, "Integrity Constraint Enforcement in the Functional Database Language PFL", in Proc. 11th British National Conference on Databases (BNCOD-11), Keele, 1993. Springer-Verlag LNCS 696.

....and describe our own solution. Section 4 concludes and outlines some other areas in which database integrity could benefit from a more practical approach. 2 Reporting Constraint Violations Despite the many proposals for integrity checking mechanisms proposed in the database literature (e.g. [27, 3, 18, 26, 8]) remarkably little has been said about the problems of reporting constraint violation to the user. Most of the proposals ignore the question completely; at best some authors [4, 6] suggest retaining the declarative specification of the constraint in some form so that it can be displayed to the ....

S. Reddi. Integrity Constraint Enforcement in the Functional Database Language PFL. In M. Worboys and A.F. Grundy, editors, Proceedings of the 11th British National Conference on Databases, pages 238--257, Keele, U.K., July 1993. SpringerVerlag.

.... in fact the language is more expressive than Datalog since set manipulation functions such as nesting, counting and unnesting can be defined [8] Integrity constraints are also more expressive than those of logic languages since cardinality and other aggregation constraints can be expressed [11]. In this paper we consider the integration of both the extensional and the intentional parts of a set of component deductive databases. The common data model (CDM) that we use for integrating the extensional parts is a binary relational ER model with subtyping. This model has fewer constructs ....

....of the paper is as follows. In Section 2 we give an overview of the functional database programming language (DBPL) that we use to define the component and integrated databases, covering only aspects of the language that are prerequisites for this paper; more comprehensive accounts can be found in [17, 7, 8, 11, 4]. In Section 3 we present our deductive database integration method. In Section 4 we compare our method with other related methods; for reasons of space this comparison is brief and a fuller discussion may be found in [21] Finally, in Section 5 we give our conclusions and indicate directions of ....

S. Reddi, "Integrity Constraint Enforcement in the Functional Database Language PFL", in Proc. 11th British National Conference on Databases (BNCOD-11), Keele, 1993. Springer-Verlag LNCS 696.

....to ECA rules is rudimentary and we plan to provide the user with tools to (re)prioritise ECA rules. Secondly, we need to investigate optimisation strategies for event detection and condition evaluation. In [Pou91, Sma91] we introduced functions that play the role of intentional relations and in [Red93] developed techniques for the efficient enforcement of integrity constraints over them. We believe that these techniques can be generalised to optimise event detection for event queries that are intentional relations. Thirdly, we need to support the database commands of Section 2 as primitive ....

Reddi, S. Integrity constraint enforcement in the functional database language PFL, Proc. 11th British National Conference on Databases, Keele, July 1993.

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