The tables are only meant for a quick scan of concept differences. To investigate the differences in more detail, the individual metamodels can be consulted to view documentation, related concepts and examples of the use of the concept. We will now briefly discuss similarities and differences of concepts based on Table 1 and Table 2. It can be seen that the Booch Class Category has no equivalent in any of the languages. Although in Booch the class is a single concept, all languages distinguish the class definition and implementation parts.
Different synonyms exist for operations in the metamodels.
Where Booch provides a single operation concept, the languages provide a richer set of operation types. Table 2 shows that important concepts in Booch design, like Cardinality and Role, do not have implementations in the OO languages. The Constraint concept that can be connected to a class in Booch is only implemented in Eiffel. However, selective exporting to a limited set of classes, as proposed by Booch, is only supported in Eiffel. Smalltalk supports neither of the export control concepts.