The figure represents the vertical storage model, in which there is a physical table corresponding to each view in the hierarchy, but each physical table stores only those attributes that are unique to its corresponding subtype.
In this illustration, the tables are
all_employeeattrs. These tables contain the attributes for the person (
address), student (
major), and employee (
mgr) types respectively.
Person_v view is based on the
all_personattrs table, the
Student_v view is based on the
all_studentattrs table, and the
Employee_v view is based on the