Abstract: A main processing system accesses a data base, which contains data records, each of which is divided into data fields. The system preferably automatically determine the type of data in each field, as well as its range of values. It then preferably determines one or more relational structures of the field data using a corresponding number of relevance measures. For each field, a preferably user-adjustable, software-generated query device is displayed, preferably in the order of the relevance measures of the respective fields. The plot of one or more fields' data relative to that of another field is initially generated using the fields in order of relevance. The relevance measure forming the basis of the field ordering, the order of fields, and the ranges of the plotted, displayed fields may be adjusted interactively by the user by moving and adjusting the various query devices.