60,155 research outputs found
A Review of integrity constraint maintenance and view updating techniques
Two interrelated problems may arise when updating a database. On one
hand, when an update is applied to the database, integrity constraints
may become violated. In such case, the integrity constraint maintenance
approach tries to obtain additional updates to keep integrity
constraints satisfied. On the other hand, when updates of derived or
view facts are requested, a view updating mechanism must be applied to
translate the update request into correct updates of the underlying base
facts.
This survey reviews the research performed on integrity constraint
maintenance and view updating. It is proposed a general framework to
classify and to compare methods that tackle integrity constraint
maintenance and/or view updating. Then, we analyze some of these methods
in more detail to identify their actual contribution and the main
limitations they may present.Postprint (published version
Structuring the process of integrity maintenance (extended version)
Two different approaches have been traditionally considered for dealing with the process of integrity constraints
enforcement: integrity checking and integrity maintenance. However, while previous research in the first approach has
mainly addressed efficiency issues, research in the second approach has been mainly concentrated in being able to
generate all possible repairs that falsify an integrity constraint violation. In this paper we address efficiency issues during
the process of integrity maintenance. In this sense, we propose a technique which improves efficiency of existing methods
by defining the order in which maintenance of integrity constraints should be performed. Moreover, we use also this
technique for being able to handle in an integrated way the integrity constraintsPostprint (published version
Protocols for Integrity Constraint Checking in Federated Databases
A federated database is comprised of multiple interconnected database systems that primarily operate independently but cooperate to a certain extent. Global integrity constraints can be very useful in federated databases, but the lack of global queries, global transaction mechanisms, and global concurrency control renders traditional constraint management techniques inapplicable. This paper presents a threefold contribution to integrity constraint checking in federated databases: (1) The problem of constraint checking in a federated database environment is clearly formulated. (2) A family of protocols for constraint checking is presented. (3) The differences across protocols in the family are analyzed with respect to system requirements, properties guaranteed by the protocols, and processing and communication costs. Thus, our work yields a suite of options from which a protocol can be chosen to suit the system capabilities and integrity requirements of a particular federated database environment
Active Integrity Constraints and Revision Programming
We study active integrity constraints and revision programming, two
formalisms designed to describe integrity constraints on databases and to
specify policies on preferred ways to enforce them. Unlike other more commonly
accepted approaches, these two formalisms attempt to provide a declarative
solution to the problem. However, the original semantics of founded repairs for
active integrity constraints and justified revisions for revision programs
differ. Our main goal is to establish a comprehensive framework of semantics
for active integrity constraints, to find a parallel framework for revision
programs, and to relate the two. By doing so, we demonstrate that the two
formalisms proposed independently of each other and based on different
intuitions when viewed within a broader semantic framework turn out to be
notational variants of each other. That lends support to the adequacy of the
semantics we develop for each of the formalisms as the foundation for a
declarative approach to the problem of database update and repair. In the paper
we also study computational properties of the semantics we consider and
establish results concerned with the concept of the minimality of change and
the invariance under the shifting transformation.Comment: 48 pages, 3 figure
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