Integrity Constraints In Relational Databases Research Articles

Temporal data modelling and integrity constraints in relational databases*

There are key issues in temporal relational data modelling such as representation of temporal data, temporal grouping identifiers, primary keys of temporal relations and temporal integrity constraints. Temporal grouping is a fundamental aspect of temporal data modelling and is the basis for the specification and enforcement of temporal integrity constraints. We extend and generalize traditional integrity constraints for the temporal domain by formally defining the temporal grouping identifier and show how it can replace a temporal primary key like a temporal atom, a temporal integrity constraint has a data and a temporal component. We also introduce the notion of consistent evolution of a temporal database that lays the foundation for an efficient implementation of temporal integrity constraints. We also provide clauses that need to be added to SQL for specifying the temporal integrity constraints.

Employing finite-state machines in data integrity problems

This paper explores the issue of group integrity of tuple subsets regarding corporate integrity constraints in relational databases. A solution may be found by applying the finite-state machine theory to guarantee group integrity of data. We present a practical guide to coding such an automaton. After creating SQL queries to manipulate data and control its integrity for real data domains, we study the issue of query performance, determine the level of transaction isolation, and generate query plans.

Minimal-change integrity maintenance using tuple deletions

We address the problem of minimal-change integrity maintenance in the context of integrity constraints in relational databases. We assume that integrity-restoration actions are limited to tuple del...

Minimal-change integrity maintenance using tuple deletions

We address the problem of minimal-change integrity maintenance in the context of integrity constraints in relational databases. We assume that integrity-restoration actions are limited to tuple deletions. We focus on two basic computational issues: repair checking (is a database instance a repair of a given database?) and consistent query answers [in: ACM Symposium on Principles of Database Systems (PODS), 1999, 68] (is a tuple an answer to a given query in every repair of a given database?). We study the computational complexity of both problems, delineating the boundary between the tractable and the intractable cases. We consider denial constraints, general functional and inclusion dependencies, as well as key and foreign key constraints. Our results shed light on the computational feasibility of minimal-change integrity maintenance. The tractable cases should lead to practical implementations. The intractability results highlight the inherent limitations of any integrity enforcement mechanism, e.g., triggers or referential constraint actions, as a way of performing minimal-change integrity maintenance.