A MODEL FOR THE GRAPHICAL REPRESENTATION OF AGGREGATE DATA

In this paper the structure and the semantic properties of the entities stored in databases, whose data are only aggregate-type data, are defined and discussed. This choice is justified by the widespread use of aggregated data without the corresponding raw data (i.e. micro-data, such as census data). Aggregated data are often derived by applying statistical aggregation (e.g. sum, count) and statistical analysis functions over micro-data, so that the relative databases are called statistical databases. For this reason in this paper such entities are called statistical object and a new statistical object representation model (Storm) based on a graph representation is proposed and discussed, as well as the canonical form of a statistical object. Also the well-formedness of a statistical object, that is its completeness and fullness of mapping and its summarizability, is discussed. Finally a brief conclusions and possible future work is given. Key Words. Statistical database, conceptual model, aggregate data model. 3. 1