Collapse the father entity set into the child entity sets

To apply this method one operates as follows:

1. one removes the “ISA” construct,
2. one moves the attributes of the father entity set to each child entity set,
3. one deletes the father entity set,
4. one attaches any father orphaned relationship sets to each child entity set.

Exercise:

1. Restructure the diagram as described above.
2. Click at compare with solution to verify your result.

Notice that this method may only be applied in case of total generalizations/specializations (in this example, employees will either be of the administrative or the technical type) or the new structure will determine a loss of information.

M3.02 E-R Restructuring