You can do these by hand, or something like

draw.io can be used for ER diagrams, or MS visio. For as much as we're going to use them, probably drawing by

hand is fine.

A university database contains information about professors $($identified by social security number, or SSN$,$ apologies for the Americanism$)$ and courses

$($identified by courseid$).$ Professors teach courses; each of the following situations concerns the Teaches relationship set.

For each situation, draw an ER diagram that describes it $($assuming no further constraints hold$).$ Each of these conditions is a separate ER diagram.

a$.$ Professors can teach the same course in several semesters, and only the most recent such offering needs to be recorded. $($Assume this condition

applies for question a$-$d$,$ f$).$

b$.$ Every professor must teach some course.

c$.$ Every professor teaches exactly one course $($no more, no less$).*-1$

d$.$ Every professor teaches exactly one course $($no more, no less$),$ and every course must be taught by some professor.

e$.$ Professors can teach the same course in several semesters, and each offering must be recorded.

f$.$ Now suppose that certain courses can be taught by a team of professors jointly, but it is possible that no one professor in a team can teach the

course. Model this situation, introducing additional entity sets and relationship sets if necessary.

Develop an ER Model for the department store as described below:

a$.$ Each employee is represented. The information about an employee is his employee number, name, address, and the department for which they

work.

b$.$ Each department is represented. The information about a department is its name, employees, manager and items sold.

c$.$ Each item sold is represented. The information about Items sold is its name, manufacturers, price, Model number $($assigned by the manufacturer$),$

and an internal item number $($assigned by the department store$).$

d$.$ Each manufacturer is represented. The information about a manufacturer is its name, address, items supplied to the store, and their price.

Draw an ER Diagram for tables from Lab$2.$