First attempts with object orientation
The idea of developing a construction kit for business software is quickly formulated, but finding suitable components for this purpose proved to be rather difficult at the beginning. The examples in textbooks on object orientation also sometimes manifested a rather technical approach, which focuses entirely on inheritance and specialisation of properties.
The familiar handling of relational models had led to an understanding of entities which was characterised by the task to be solved and the necessity to avoid redundancy as far as possible.
A debate about what exactly constitutes an entity - what an object - what defines it comprehensively was new. Previously used terms were now questioned more closely, a process of abstraction began.
If relational entities are seen more as a compilation of individual data fields useful from an application point of view, an object-oriented view additionally questions the common properties of the data fields in the ensemble.