Verification Technology for Object-Oriented/XML Transactions

Unlike the existing object-oriented and other database technologies, database schemas in the technology developed in this research are equipped with very general integrity constraints specified in a declarative, logic-based fashion. These declarative specifications are expressed in object-oriented assertion languages and they apply to transactions that are implemented in a full-fledged, mainstream object-oriented programming language. The model of transactions is based on more advanced features of object-oriented type systems, the ownership model, and very general constraints. The main distinction in comparison with other database technologies is that transactions can be verified to satisfy the schema integrity constraints. The two main contributions of this paper are object-oriented schemas equipped with integrity constraints and static verification of transactions with respect to the integrity constraints. Solutions to these open problems have been out of reach so far. Furthermore, transaction verification is not only largely static, but it is also automatic, so that the subtleties of the underlying verification technology are hidden from the users. In addition to static verification, the technology offers dynamic enforcement of the integrity constraints when necessary. The overall outcome is a significant increase in data integrity along with run-time efficiency and reliability of transactions.

We address the key issues of temporal data modeling and temporal integrity constraints in the temporal extensions to the relational data model in attribute and tuple time stamping. These issues include representation of temporal data, temporal grouping identifiers, primary keys of temporal relations and other forms of temporal integrity constraints. We extend the traditional integrity constraints to the temporal domain. In tackling subtle issues temporality creates, we conceptualize that a temporal integrity constraint has a data and a temporal (time) component. The time component of a temporal integrity constraint limits the attribute values to the lifespan of an object (tuple). We also generalize single state integrity constraints to multi-state temporal integrity constraints and apply them to existential and referential integrity. We provide algorithms for enforcing the two types of temporal integrity constraints.

In this demonstration, we present a new definition of integrity constraint that is more powerful for anomalous data discovery. In our definition, a constraint is functioned on both categorical and numerical attributes in relational tables, as well as their derivative attributes, leading to a huge search space. Furthermore, we are the first to take into account attribute value distribution as part of a constraint. Based on the proposed integrity constraint, we build AUDITOR on top of relational tables from the industry of healthcare auditing and demonstrate its effectiveness and ease-of-use for domain experts to discover anomalous data.

A new model with invariant-based language effectively handles data-driven rules in databases and uses the rules' inherent semantic properties and supporting mechanisms to meet high-level language requirements. It is an extension of the basic PARDES model developed by Opher Etzion in 1990 to support derivations and integrity constraints in databases. The model's invariant-based language, unlike other programming languages, can follow data-driven rules' semantic properties. Such rules are activated by modifications of data items in a database, and they play an important role in many applications that maintain complex relationships between data items or interdependencies between parts of the database. Applications include expert systems, real-time databases, simulations, and decision-support systems. The authors present requirements for choosing an adequate programming style that uses data-driven rules. These requirements are based on software-engineering criteria such as compatibility with a high-level language and verifiability of the rule language. The authors show that contemporary database programming styles fail to meet these requirements, and they present the invariant-based language as a viable solution.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A model and a language for specifying spatial integrity constraints in pictorial databases are presented. Spatial integrity constraints are assertions about the correct behavior of database systems that specify acceptable database states and state transitions. They also serve as restrictions on positions occupied by objects in a picture. The language presented primarily uses pictures to specify constraints. The constraint pictures depict unacceptable database states. A data model provides the basic semantics for picture interpretation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Integrity constraints are an essential part of modern schema de nition languages. They are useful for semantic speci cation, update consistency control, query optimization, information preservation, etc. In this paper, we propose UCM, a model of integrity constraints for XML that is both simple and expressive. Because it relies on a single notion of keys and foreign keys, the UCM model is easy to use and makes formal reasoning possible. Because it relies on a powerful type system, the UCM model is expressive, capturing in a single framework the constraints found in relational databases, objectoriented schemas and XML DTDs. We study the problem of consistency of UCM constraints, the interaction between constraints and subtyping, and algorithms for implementing these constraints.

The main goal of this chapter is to arrive at a coherent technology for deriving efficient SQL triggers from declarative specifications of arbitrary integrity constraints. The user may specify integrity constraints declaratively as closed queries in predicate calculus syntax (i.e., sentences in the language of first-order logic, abbr. FOL), as datalog denials, as query conditions in SQL WHERE clauses, or in some other, possibly more user-friendly manner (e.g., via a dialog-driven graphical or natural language interface which internally translates to equivalent WHERE clause conditions). As we are going to see, the triggers derived from such specifications behave such that whenever some update event would violate any of the integrity constraints, one or several of the triggers derived from that constraint are activated in order to enforce the constraint. That is, the violation is either prevented by rolling back the update or repaired instantly by subsequent further updates.

This paper intends to classify, review, and compare the existing languages for the specification of spatial integrity constraints at the conceptual level. We classify these languages into natural, visual, first-order logic, and hybrid and review their syntax and semantics. We compare these language categories based on expressiveness and pragmatics qualities. The results of this study show that controlled natural languages and natural hybrid languages with pictograms are good candidates for expressing spatial integrity constraints at the conceptual level of spatial databases. At the end, we identify new research challenges that should be addressed in this domain in order to facilitate spatial integrity constraint specification and representation.

This paper presents a static signature verification system based on a region-oriented strategy. For this purpose, a suitable technique is proposed for the analysis of local stability in static signature and stable regions are selected during the enrollment phase. In the running phase, an unknown specimen is verified through the analysis of the selected regions, on the basis of a well-defined similarity measure. The experimental results, carried out on signatures from the GPDS database, demonstrate the proposed approach.

A multilevel relational database with tuple-level labeling is a relational database together with a mapping, which associates a set of levels in a security lattice with every tuple in every relation in the database. Integrity constraints represent the invariant properties of data in a multilevel relational database. We study the relationship between integrity and secrecy, and show that they are not necessarily in fundamental conflict. We identify common classes of constraints whose enforcement is free of both static and dynamic inference channels. We also extend the integrity checking mechanism by proper update semantics to remove dynamic inference channels in the enforcement of more general classes of constraints.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Semantics of recursive relationships in entity-relationship model

This chapter reviews the notions of security and dependability properties from the perspective of software engineering, providing the reader with a technical background on dynamic verification and runtime monitoring techniques. The chapter covers the technical background on security and dependability properties with system verification through dynamic verification or monitoring. The authors initially provide a short overview of the security and dependability properties themselves. Once definitions of security and dependability properties are introduced, they present a critical analysis of current research on dynamic verification by presenting general purpose and security oriented dynamic verification approaches.

While specification languages for integrity constraints for XML data have been considered in the literature, actual technologies and methodologies for checking and maintaining integrity are still in their infancy. Triggers, or active rules, which are widely used in previous technologies for the purpose are still rather untested in XML databases. We present the first steps towards a methodology for design and verification of triggers that maintain integrity in XML databases. Starting from a specification of the integrity constraints plus a collection of XPath expressions describing the possible updates, the method indicates trigger conditions and correctness criteria to be met by the trigger code supplied by a developer or possibly automatic methods. We show examples developed in the Sedna XML database system which provides a running implementation of XML triggers.

On the satisfiability of dependency constraints in entity-relationship schemata

The object-oriented data model TM is a language that is based on the formal theory of FM, a typed language with object-oriented features such as attributes and methods in the presence of subtyping. The general (typed) set constructs of FM allow one to deal with (database) constraints in TM.The paper describes the theory of FM, and discusses the role that set expressions may play in conceptual database schemas. Special attention is paid to the treatment of constraints, and a three-step specification approach is proposed. This approach results in the formal notion of database universe stated as an FM expression.