A theorem prover-based analysis tool for object-oriented databases

We present a theorem-prover based analysis tool for object-oriented database systems with integrity constraints. Object-oriented database specifications are mapped to higher-order logic (HOL). This allows us to reason about the semantics of database operations using a mechanical theorem prover such as Isabelle or PVS. The tool can be used to verify various semantics requirements of the schema (such as transaction safety, compensation, and commutativity) to support the advanced transaction models used in workflow and cooperative work. We give an example of method safety analysis for the generic structure editing operations of a cooperative authoring system

Path constraints in semistructured databases

AbstractWe investigate a class of path constraints that is of interest in connection with both semistructured and structured data. In standard database systems, constraints are typically expressed as part of the schema, but in semistructured data there is no explicit schema and path constraints provide a natural alternative. As with structured data, path constraints on semistructured data express integrity constraints associated with the semantics of data and are important in query optimization. We show that in semistructured databases, despite the simple syntax of the constraints, their associated implication problem is r.e. complete and finite implication problem is co-r.e. complete. However, we establish the decidability of the implication and finite implication problems for several fragments of the path constraint language and demonstrate that these fragments suffice to express important semantic information such as extent constraints, inverse relationships, and local database constraints commonly found in object-oriented databases

Development of an Assertion Model of Integrity Constraints in Object-Oriented Databases

Object-Oriented Databases (OODBs) have been designed to support large and complex programming projects. The data accuracy, consistency, and integrity in OODBs are extremely important for developers and users. Checking the integrity constraints in OODBs is a fundamental problem in database design. Existing OODB Management Systems (OODBMSs) lack to a capability of an ad-hoc declarative specification of enforcing and maintaining integrity constraints that are appeared among attributes in association, composition, and inheritance hierarchies' relationships. A critical problem in the existing OODBs is that they cannot support User-Defmed Constraints (UDCs) that can be defmed in classes with composition (logical or physical composition) and inherence (single or mUltiple inheritance) hierarchies. Integrity constraints in the current OODBMSs are maintained either by disallowing and rolling back transaction or modifying operations that may produce a violation. The constraints must be maintained in the backward direction along the class composition hierarchy as well as in the forward direction. In this work an Assertion Model of Integrity Constraints (AMIC) is proposed. The AMIC keeps the derivation path along with the attributes' relationships that are derived from association, composition, and inheritance hierarchies. The AMIC techniques are designed to implement the needed functions that are collecting the attributes' relationships and checking the integrity constraints. Moreover, AMIC keeps UDCs with their relationships in both single classes and multilevel classes (intra-class and inter-class). Furthermore, the AMIC can maintain constraints in a single object and a set of distributed objects (intra-object and inter-object). Therefore, this makes the new model extendable and can be integrated with any existing constraints' service. A new technique called Detection Method (DM) isdesigned to check the Object Meta Data (OMD) to detect the constraints violation before it occurs. The AMIC is designed for both Centralized Integrity Maintenance (CIM) and Application-Oriented Integrity Maintenance (AOIM). The AMIC can also enforce and maintain structural and logical integrity constraints, in addition to enforce and maintain redundant, inconsistent, and duplicate constraints

Mapping between Alloy specifications and database implementations

The emergence of lightweight formal methods tools such as Alloy improves the software design process, by encouraging developers to model and verify their systems before engaging in hideous implementation details. However, an abstract Alloy specification is far from an actual implementation, and manually refining the former into the latter is unfortunately a non-trivial task. This paper identifies a subset of the Alloy language that is equivalent to a relational database schema with the most conventional integrity constraints, namely functional and inclusion dependencies. This semantic correspondence enables both the automatic translation of Alloy specifications into relational database schemas and the reengineering of legacy databases into Alloy. The paper also discusses how to derive an object-oriented application layer to serve as interface to the underlying database

Towards Intelligent Databases

This article is a presentation of the objectives and techniques of deductive databases. The deductive approach to databases aims at extending with intensional definitions other database paradigms that describe applications extensionaUy. We first show how constructive specifications can be expressed with deduction rules, and how normative conditions can be defined using integrity constraints. We outline the principles of bottom-up and top-down query answering procedures and present the techniques used for integrity checking. We then argue that it is often desirable to manage with a database system not only database applications, but also specifications of system components. We present such meta-level specifications and discuss their advantages over conventional approaches

Compensation methods to support generic graph editing: A case study in automated verification of schema requirements for an advanced transaction model

Compensation plays an important role in advanced transaction models, cooperative work, and workflow systems. However, compensation operations are often simply written as a^−1 in transaction model literature. This notation ignores any operation parameters, results, and side effects. A schema designer intending to use an advanced transaction model is expected (required) to write correct method code. However, in the days of cut-and-paste, this is much easier said than done. In this paper, we demonstrate the feasibility of using an off-the-shelf theorem prover (also called a proof assistant) to perform automated verification of compensation requirements for an OODB schema. We report on the results of a case study in verification for a particular advanced transaction model that supports cooperative applications. The case study is based on an OODB schema that provides generic graph editing functionality for the creation, insertion, and manipulation of nodes and links

Automatic Verification of Transactions on an Object-Oriented Database

In the context of the object-oriented data model, a compiletime approach is given that provides for a significant reduction of the amount of run-time transaction overhead due to integrity constraint checking. The higher-order logic Isabelle theorem prover is used to automatically prove which constraints might, or might not be violated by a given transaction in a manner analogous to the one used by Sheard and Stemple (1989) for the relational data model. A prototype transaction verification tool has been implemented, which automates the semantic mappings and generates proof goals for Isabelle. Test results are discussed to illustrate the effectiveness of our approach

Steps Towards a Method for the Formal Modeling of Dynamic Objects

Fragments of a method to formally specify object-oriented models of a universe of discourse are presented. The task of finding such models is divided into three subtasks, object classification, event specification, and the specification of the life cycle of an object. Each of these subtasks is further subdivided, and for each of the subtasks heuristics are given that can aid the analyst in deciding how to represent a particular aspect of the real world. The main sources of inspiration are Jackson System Development, algebraic specification of data- and object types, and algebraic specification of processes