de Bert Brock

An Object-Oriented Framework for Managing Cooperating Legacy Databases

We describe a general semantic framework for precise specification of so-called database federations. A database federation provides for tight coupling of a collection of heterogeneous legacy databases into a global integrated system. Our approach to database federation is based on the UML/OCL data model, and aims at the integration of the underlying database schemas of the component legacy systems to a separate, newly defined integrated database schema. Our approach to coupling of component databases into a global, integrated system is based on mediation. Our major result is that mediation in combination with a so-called integration isomorphism integrates component schemas without loss of constraint information; i.e., constraint information available at the component level remains intact after integration on the level of the virtual federated database. Our approach to integration also allows for specification of additional inter-database constraints between the component databases.

Supporting the creation of business re-engineering ideas

Purpose – The purpose of this paper is to offer systematic support for the creation of business re‐engineering ideas to exploit new communication channels (such as internet, mobile phone, SMS, and RFID). This approach is designed to enable users to develop new ways of doing business.Design/methodology/approach – Relevant parameters as well as their possible values are identified. These parameters are used to generate a questionnaire containing all possible option descriptions. This (ordered) questionnaire offers systematic support for the creation of business re‐engineering ideas that exploit new communication channels. The methodology is completed by an approach that supports the assessment and selection of new business ideas. A tool that supports this approach has been designed, built, and tested.Findings – The relevant parameters are found to be communication channel, communication mode (informational, interactional, or transactional), stakeholders group, stakeholders status (current or new), product/s...

Declarative semantics of transactions in ORM

In order to specify databases completely at the conceptual level, conceptual database specification languages should contain a data definition (sub)language (DDL), for specifying data structures (+constraints), a data retrieval (sub)language (DRL), for specifying queries, as well as a (declarative) data manipulation (sub)language (DML), for specifying transactions.Object Role Modeling (ORM) is a powerful method for designing and querying database models at the conceptual level. By means of verbalization the application is also described in natural language as used by domain experts, for communication and validation purposes. ORM currently comprises a DDL and a DRL (ConQuer). However, the ORM-method does not yet contain an expressive DML for specifying transactions at the conceptual level.In an earlier paper we designed a syntactic extension of the ORM-method with a DML for specifying transactions at the conceptual level in a purely declarative way. For all transactions we proposed syntaxes, verbalizations, and diagrams. However, we did not give a formal semantics then.The purpose of this paper is to add a clear, formal and purely declarative semantics to the proposed ORM-transactions. The paper also formally defines rollbacks and illustrates everything with examples (including a solution to a well-known transaction specification problem). The extension of ORM with an expressive set of completely declaratively specified transactions makes ORM complete as a database specification method at the conceptual level. Transactions and rollbacks are formally defined in a declarative way.Transactions with clear formal population semantics are added to the method ORM.This makes ORM complete as a database specification method at the conceptual level.Also a solution to a well-known transaction specification problem is given as an example.