Abstract
Obtaining and applying information is considered as a critical task in the modern informationized society. Finding the one's necessary information and processing it into a detailed knowledge are becoming more priortized in the enormous amount of information. Data modelling is the process that does not only reflect the demands of the user but the one that also facilitates the user's comprehension of the model itself. Ultimately, data modelling fully supports the processes that are requisite for the implementation of a data base and minimizes the alternations of the model during the development of applications.