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Table: UNIFORM
UCode UName UColor
1 Shirt White
2 Pant Grey
3 Skirt Grey
4 Tie Blue
5 Socks Blue
6 Belt Blue
a. Can they insert the following tuples into the UNIFORM relation? Give reasons in support of your answer.
i. 7, Handkerchief, NULL
ii. 4, Ribbon, Red
iii. 8, NULL, White
b. Can they insert the following tuples into the COST relation? Give reasons in support of your answer.
i. 7, S, 0
ii. 9, XL, 100
Ans. a.
i. Yes, because Ucode 7
ii. No, because Ucode 4 is already assigned to Tie and Ucode can’t have duplicate values being a primary key.
iii. No, because Uname is following the Not Null constraint.
b.
i. No, as it is violating check constraints
ii. Yes
11. In a multiplex, movies are screened in different auditoriums. One movie can be shown in more than one auditorium. In order to maintain
the record of movies, the multiplex maintains a relational database consisting of two relations viz. MOVIE and AUDI respectively as
shown below:
Movie(Movie_ID, MovieName, ReleaseDate)
Audi(AudiNo, Movie_ID, Seats, ScreenType, TicketPrice)
a. Is it correct to assign Movie_ID as the primary key in the MOVIE relation? If no, then suggest an appropriate primary key.
b. Is it correct to assign AudiNo as the primary key in the AUDI relation? If no, then suggest appropriate primary key.
c. Is there any foreign key in any of these relations?
Ans a. Yes, we can use Movie_ID as the primary key because each movie can have unique values.
b. No, AudiNo along with Movie_ID should be made as the primary key. That is, the relation should have a composite primary key as
(AudiNo, Modie_ID)
c. Yes, Movie_ID is a foreign key in the AUDI table, which refers to the Movie_ID column of MOVIE table.
12. For the above given database STUDENT-PROJECT, answer the following:
Student-Project
Database
Table: STUDENT
Roll No Name Class Section Registration_ID
11 Mohan XI 1 IP-101-15
12 Sohan XI 2 IP-104-15
21 John XII 1 CS-103-14
22 Meena XII 2 CS-101-14
23 Juhi XII 2 CS-101-10
Table: PROJECT
ProjectNo PName SubmissionDate
101 Airline Database 12/01/2018
102 Library Database 12/01/2018
103 Employee Database 15/01/2018
104 Student Database 12/01/2018
105 Inventory Database 15/01/2018
106 Railway Database 15/01/2018
Database Concepts and the Structured Query Language 289

