Question

Create an ER diagram (using ERDPlus) for the Qwerty Bus Company based on the following requirements.

Show entities, relationships, and attributes. Qwerty Bus Co. is a bus charter company keeps track of: For each employed driver: fullname (composed of fname and lname), birthdate, age, unique SSN, unique dln (driver’s license number). For each bus owned: unique blpn (bus license plate number), make, model, year, no_of_seats. For each charter assignment: unique caid (charter assignment id), datebegin, timebegin, dateend, timeend, startlocation, endlocation. Additional requirements: Each driver can be assigned to a number of charter assignments but does not have to be assigned to any. Each bus can be assigned to a number of charter assignments but does not have to be assigned to any. Each charter assignment must have one driver and one bus assigned to it. Each driver is certified to drive one or more buses. Each bus must have at least one driver certified for it.

Answer 1

To represent the entities, relationships, and attributes of the Qwerty Bus Company, we can create an ER diagram. The entities include Driver, Bus, and Charter Assignment, and there are several relationships between them. Each entity also has specific attributes.

Step-by-step explanation:

ER Diagram for Qwerty Bus Company

To represent the entities, relationships, and attributes of the Qwerty Bus Company, we can create the following ER diagram:

Entities:

Driver (sssn, fname, lname, birthdate, age, dln)

Bus (blpn, make, model, year, no_of_seats)

Charter Assignment (ca_id, datebegin, timebegin, dateend, timeend, startlocation, endlocation)

Relationships:

Driver - Charter Assignment: Many-to-Many relationship

Bus - Charter Assignment: Many-to-Many relationship

Driver - Bus: Many-to-Many relationshi

Attributes:

Each driver can have one or more charter assignments, so the Driver entity has a multi-valued attribute (Charter Assignment).

Each bus can have one or more charter assignments, so the Bus entity has a multi-valued attribute (Charter Assignment).

Each driver is certified to drive one or more buses, so the Driver entity has a multi-valued attribute (Bus).

Each bus must have at least one driver certified for it, so the Bus entity has a minimum cardinality constraint (Driver).

This ER diagram captures the relationships and attributes as described in the requirements for the Qwerty Bus Company.