There are many methods in the area of data warehousing to define requirements for the development of the most appropriate conceptual model of a data warehouse. There is no universal consensus about the best method, nor are there accepted standards for the conceptual modeling of data warehouses. Only few conceptual models have formally described methods how to get these models. Therefore, problems arise when in a particular data warehousing project, an appropriate development approach, and a corresponding method for the requirements elicitation, should be chosen and applied. Sometimes it is also necessary not only to use the existing methods, but also to provide new methods that are usable in particular development situations. It is necessary to represent these new methods formally, to ensure the appropriate usage of these methods in similar situations in the future. It is also necessary to define the contingency factors, which describe the situation where the method is usable.This chapter represents the usage of method engineering approach for the development of conceptual models of data warehouses. A set of contingency factors that determine the choice between the usage of an existing method and the necessity to develop a new one is defined. Three case studies are presented. Three new methods: userdriven, data-driven, and goal-driven are developed according to the situation in the particular projects and using the method engineering approach.

A typical data warehouse report is the dynamic representation of some objects' behaviour or changes of objects' properties. If this behaviour is changing, it is difficult to make such reports in an easy way. It is possible to use the fact splitting to make this task simpler and more comprehensible for users. In the presented paper two solutions of splitting facts by using weights are described. One of the possible solutions is to make the proportional weighting accordingly to splitted record set size. It is possible to take into account the length of the fact validity time period and the validity time for each splitted fact record.

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