Merging and Outsourcing Information Systems with UML

Businesses can change their business structure by merging with other companies or, on the other end of the spectrum, by smoothly outsourcing some of their business processes to other more specialized parties. In this paper, we will concentrate on conceptual modelling of merging and outsourcing information systems. Merging of a collection of information systems will be defined as the construction of a global information system that contains exactly the functionality of the original collection of systems. Such global information systems are called federated information systems, when we wish to address the situation where the component systems are so-called legacy systems; that is, systems that are given beforehand and that are to interoperate in an integrated single framework in which the legacy systems are to maintain as much as possible their respective autonomy. Two major problems in constructing federated information systems concern achieving and maintaining consistency, and a uniform representation of the data on the global level of the federation. The process of creation of uniform representations of data is known as data extraction, whereas data reconciliation is concerned with resolving data inconsistencies. Outsourcing of an information system, on the other hand, will be defined as the handing over of part of the functionality of the original system to an outside party (the supplier). Such functionality typically involves one or more operations, where each operation satisfies certain input and output requirements. These requirements will be defined in terms of the ruling service level agreements (SLAs). We will provide a formal means to ensure that the outsourcing relationship between outsourcing party and supplier, determined by an SLA, satisfies specific correctness criteria. Formal specifications, as offered in this paper, can prove their value in the setup and evaluation of outsourcing contracts. We shall describe a uniform semantic framework for specification of both federated and outsourced information systems based on the UML/OCL data model. In particular, we will show that we can represent so-called exact views in UML/OCL, providing