Class is a database field, specified as either Diagram, Symbol or Definition.

When entering the class specification in the Add Report dialog, it is important to start from the right place, since the time required to run the report is directly related to the number of records that are read. It is often advantageous to include an extra level of extraction criteria in the beginning of the report, even if nothing is printed at that level. An example of this is provided (see Example – using extraction specification levels).

If a text editor is used to write the report, the class can also be specified as the Class Number; the number which indicates a diagram (Class Number = 1), a symbol (Class Number = 2), or a definition (Class Number = 3).