Question

Consider the following relational database to manage concert and ticket sales. The relations are artist, concert, venue, seat, ticket, and fan. The schemas for these relations (with primary key attributes underlined) are:

Artist-schema = (artistname, type, salary)

Concert-schema = (artistname, date, venuename, artistfees)

Venue-schema = (venuename, address, seating_capacity)

Seat-schema=(venuename, row, seatnumber)

Ticket-schema = (fanID, date, venuename, row, seatnumber)

Fan-schema = (fanID, name, address, creditcardno)

Where:

• artistname is a unique name for the artist (because of trademark/copyright rules no two artists have the same name).

• type is an attribute whose value is chosen from “music”, “comedy”, “juggling”, or “other”

• artistfees is a real number greater than 0

• fanID is a unique ID given to a customer

• creditcardno is a 16 digit credit card number starting with a 4 or a 5. a)

1 Draw a schema diagram for this database. Be sure to indicate all foreign keys implied by the attribute names and primary keys in the relation schemas.

2) Does this database schema allow for one fan to have multiple tickets for a given concert? Justify.

3) Does this database schema allow for multiple artists to play a given venue on a particular date? Justify.

4) Could the date attribute in ticket be a foreign key referencing only the date attribute in concert? Justify.

5) Why would a foreign key in ticket referencing venue NOT provide any additional constraints?

Answer 1

Answer :

1)

2)

The database scheme will allow one fan to have multiple tickets for a given concert. If we see the table Fan there the fanID is the primary key but where as in the ticket table the fanid is acting as a foreign key. So multiple entries can be there referencing the foreign key.

3)

The database schema will allow multiple artists to play in a given venue on a particular date. The venue scheme stores the artist name who are going for the venue. So the artist can be more than one in particular venue for the particular date.

4)

Yes the date attribute in ticket be a foreign key referencing only the date attribute in concert. This is because the ticket contains the date for the venue when the concert is and hence the date in the concert table must be same to match with the values.

5)

A foreign key in ticket referencing venue NOT provide any additional constraints this is because for a particular ticket the venue will be fixed. Hence no additional constraints are needed.