INFORMATION SYSTEMS IN MANAGEMENT IV

dimension-based model. Also, to speed data retrieval, these data are often storedmultiple times - in their most granular form and in summarized forms called aggregates.Data of data warehouse are gathered from the operational systems and heldin the data warehouse even after the data has been purged from the operationalsystems.4. BUSINESS AND LOGICAL MODELINGTo build a conceptual model of a data warehouse we should define a businessmodel of an undertaking (of an enterprise) and thus we should analyze:• Query requirements• Data structure changes• Time of answering• Resource management• Interface and verification tools• System of making backups and of data recoveryIn addition we can distinguish some detailed issues: time of answering in queries,data resource management, using operational costs and so on. By businessprocess we mean an essential process of a given business (of an enterprise) whichis engaged in storing and managing useful data. Business process examples areorders, expedition, marketing and so on.Business modeling consists of three tasks: strategic analysis, business modelcreation, metadata creation. At the beginning strategic analysis is made for a givenenterprise to identify and define most important business processes and their priorities.Next the business model is developed – detailed business requirements aregiven for all business processes and source data are verified to get proper requirements.Metadata are created at the beginning of the design process and they areresults of the business process analysis. This information will be very useful inconsecutive phases, when we create the conceptual model.During strategic analysis we try to obtain a simple and approximate model of adata warehouse. We must identify and try to understand main (key) business processesof the considered enterprise and analyze their hierarchy and select them properlyfor implementation. Moreover, we should understand and apply general rulesof the considered business to achieve the best results. Then we should have anaccess to all data, aid customers of this business, observe competitors and try tofind the advantage of their activity. Moreover we should be ready for variouschanges in business and quickly react to such changes.During strategic interviews we identify and analyze key business processes andwe might check hierarchy of them with respect to the Return Of Investment sizeand with respect to their strategic value (concerning their meaning in makingdecisions) and to the implementation ease and time.51