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

Effect preservation in transaction processing in rule triggering systems

Rules provide an expressive means for implementing database behavior: They cope with changes and their ramifications. Rules are commonly used for integrity enforcement, i.e., for repairing database actions in a way that integrity constraints are kept. Yet, Rule Triggering Systems fall short in enforcing effect preservation, i.e., guaranteeing that repairing events do not undo each other, and in particular, do not undo the original triggering event. A method for enforcement of effect preservation on updates in general rule triggering systems is suggested. The method derives transactions from rules, and then splits the work between compile time and run time. At compile time, a data structure is constructed, that analyzes the execution sequences of a transaction and computes minimal conditions for effect preservation. The transaction code is augmented with instructions that navigate along the data structure and test the computed minimal conditions. This method produces minimal effect preserving transactions, and under certain conditions, provides meaningful improvement over the quadratic overhead of pure run time procedures. For transactions without loops, the run time overhead is linear in the size of the transaction, and for general transactions, the run time overhead depends linearly on the length of the execution sequence and the number of loop repetitions. The method is currently being implemented within a traditional database system

Knowledge Representation Concepts for Automated SLA Management

Outsourcing of complex IT infrastructure to IT service providers has increased substantially during the past years. IT service providers must be able to fulfil their service-quality commitments based upon predefined Service Level Agreements (SLAs) with the service customer. They need to manage, execute and maintain thousands of SLAs for different customers and different types of services, which needs new levels of flexibility and automation not available with the current technology. The complexity of contractual logic in SLAs requires new forms of knowledge representation to automatically draw inferences and execute contractual agreements. A logic-based approach provides several advantages including automated rule chaining allowing for compact knowledge representation as well as flexibility to adapt to rapidly changing business requirements. We suggest adequate logical formalisms for representation and enforcement of SLA rules and describe a proof-of-concept implementation. The article describes selected formalisms of the ContractLog KR and their adequacy for automated SLA management and presents results of experiments to demonstrate flexibility and scalability of the approach.Comment: Paschke, A. and Bichler, M.: Knowledge Representation Concepts for Automated SLA Management, Int. Journal of Decision Support Systems (DSS), submitted 19th March 200

Coase and Car Repair: Who Should Be Responsible for Emissions of Vehicles in Use?

This paper examines the current assignment of liability for in-use vehicle emissions and suggests some alternative policies that may reduce the cost and increase the effectiveness. The authors first discuss the cost, performance and incentives under current Inspection and Maintenance (I/M) programs, using the recently implemented Arizona "Enhanced I/M" program as an example. These programs were designed to identify and repair vehicles with malfunctioning emission control systems. Since their inception, however, I/M programs have been plagued by transaction costs that have drastically raised the cost of I/M as well as limited its effectiveness. These transaction costs fall into three categories: emission monitoring, repair avoidance, and non-transferability of emission reductions. The authors argue that most of these transaction costs can be attributed to the current assignment of liability for I/M to motorists, and they examine the potential for other liability assignments to reduce transaction costs and improve program efficiency. Among the alternative institutional arrangements discussed are greater imposition of liability on manufacturers, emission repair subsidies, repair liability auctions, and vehicle leasing.

Rethinking the Theory of Legal Rights

In the economic approach to law, legal rights are designed, in part, to overcome the conditions under which markets fail. In correcting for market failure, economic analysis endorses two rules for assigning legal rights. The first specifies the allocation of rights under conditions of rational cooperation, full information and zero transaction costs. Provided that exchange is available and that obstacles to exercising it are insignificant, rational cooperators will negotiate around inefficiencies. Under these conditions, legal rights are not assigned in order to establish optimal levels of resource deployment directly; rather, they establish well-defined entitlements or negotiation points which create a framework in which mutually advantageous bargains leading to optimal outcomes can be realized. This role of legal rights in securing optimal outcomes is suggested by the Coase Theorem. The second rule for assigning legal rights specifies the procedures to be followed in the event the conditions of full information, rational cooperation and zero transaction costs are inadequately satisfied. Where impediments to successful negotiations are substantial, inefficiencies in the initial allocation may not be overcome through mutually advantageous exchange. Unable to rely upon the exchange process to overcome inefficiencies, a court must allocate entitlements efficiently from the outset. In doing so, the court continues to rely upon the exchange process, though in a different manner. Instead of relying upon exchange to rectify inefficiencies, including inefficient judicial decisions, the court relies upon the market paradigm to help it identify the efficient outcome it seeks to replicate

Rethinking the Theory of Legal Rights

In the economic approach to law, legal rights are designed, in part, to overcome the conditions under which markets fail. In correcting for market failure, economic analysis endorses two rules for assigning legal rights. The first specifies the allocation of rights under conditions of rational cooperation, full information and zero transaction costs. Provided that exchange is available and that obstacles to exercising it are insignificant, rational cooperators will negotiate around inefficiencies. Under these conditions, legal rights are not assigned in order to establish optimal levels of resource deployment directly; rather, they establish well-defined entitlements or negotiation points which create a framework in which mutually advantageous bargains leading to optimal outcomes can be realized. This role of legal rights in securing optimal outcomes is suggested by the Coase Theorem. The second rule for assigning legal rights specifies the procedures to be followed in the event the conditions of full information, rational cooperation and zero transaction costs are inadequately satisfied. Where impediments to successful negotiations are substantial, inefficiencies in the initial allocation may not be overcome through mutually advantageous exchange. Unable to rely upon the exchange process to overcome inefficiencies, a court must allocate entitlements efficiently from the outset. In doing so, the court continues to rely upon the exchange process, though in a different manner. Instead of relying upon exchange to rectify inefficiencies, including inefficient judicial decisions, the court relies upon the market paradigm to help it identify the efficient outcome it seeks to replicate

Brownfields Redevelopment in Wisconsin: Program, Citywide, and Site-Level Studies

In this paper, the second installment of our three-part study on the development of brownfields policy in the state of Wisconsin, we use case studies to explore the implementation of the policy at three scales: 1) two statewide initiatives, the Voluntary Party Liability Exemption process and the Sustainable Urban Development Zone program; 2) the efforts of two Wisconsin cities, West Allis and Wausau, to promote brownfields redevelopment across their neighborhoods; and 3) project-specific uses of institutional, regulatory, and financial innovations to encourage the revitalization of specific areas. Throughout the paper, we focus on the role of economic incentives, regulatory flexibility, regulatory structure, and the behavioral culture of brownfields stakeholders. We base our work on interviews of nearly 70 individuals from public, private-for-profit, private-nonprofit, and tribal organizations.Brownfields, contamination, hazardous waste, regulatory reform, Wisconsin