NOTE: MORE THAN ONE ANSWER OF THE GIVEN OPTIONS MAY BE CORRECT. Domain Consider

Question

NOTE: MORE THAN ONE ANSWER OF THE GIVEN OPTIONS MAY BE CORRECT.

Domain Consider a cinema database that stores ticket sales. Each Screening of a movie is stored in a relation with an id, the name of the movie, the time of the screening, and which screen it is shown on. An employee is stored with an id, the name, the address where the employee lives and the phone number. A ticket is stored with the id of the employee that sold the ticket, the id of the screening, the timestamp when it was sold, the price of the ticket and the discount type (if there was a discount). The database schema then is SCREENING sld, movie, time, screen) . EMPLOYee- feld, name, address,phone) TICKET - feld, sId, timestamp, price, discount This results in a database given by the following relations Ticket tId eld sld timestamp price discount 1 1 1 2018-03-23 3:14pm 10 none 2 3 4 2018-03-23 3:16pm 8 student 3 3 2 2018-03-23 3:16pm 8 student 4 1 4 2018-03-23 5:48pm 10 none 5 1 3 2018-03-23 5:48pm lecturer Employee eld ame address phone 1 Tyler Durden 537 Paper Street(288) 555-0153 2 Diane Selwyn 1612 Havenhurst Dr. (255) 555-7614 3 Tyler Durden 1612 Havenhurst Dr. (255) 555-7614 Screening sld movie time screen 2018-03-23 7pm Screen 1 2018-03-23 7pm Screen 2 1 Nosferatu 2 Head On 3 Bloody Pit of Horror 2018-03-23 9pm Screen 1 4 The Following 2018-03-23 9pm Screen 2

Explanation / Answer

Solution:

A superkey is set of relations which can be used to uniquely determine any of the row of the table.

1)

So according to the above definition, All four choices satisfy the definition of the super key for the Employee table.

2)

last three options are correct

there are two rows which matched for the set {price, discount} which means it does not uniquely define the row of the table.

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