
telephoneExtensionNo is adequate because they cannot determine employeeNo, there
being several employees per room and per extension.
5. (a)
(b) The only candidate identifier is {employeeNo, telephoneExtensionNo};
employeeNo alone is no longer sufficient (compare 4(b)) because the same
employeeNo may occur in several rows of the table, each occurrence being associated
with a different telephoneExtensionNo.
6. Consultant (consultantNo, consultantName)
Project (projectNo, projectTitle)
ConsultantProject (consultantNo, projectNo)
A consultant who is not assigned to any project will appear in Consultant but not in
ConsultantProject. Similarly, a project that ...