Questions & Answers of ER-model

Question No. 117

An ER model of a database consists of entity types A and B. These are connected by a relationship R which dose not have its own attribute. Under which one of the following condiditons, can the relational table for R be merged with that of A?

Question No. 48

Consider an Entity-Relationship(ER) model in which entity sets E1 and E2 are connected by an m:n relationship R12. E1 and E3 are connected by a 1: (1 on the side of E1 and n on the side of E3) relationship R13.

E1 has two single-valued attributes a11 and a12 of which a11 is the key attribute. E2 has two single-valued attributes a21 and a22 of which is the key attribute. E3 has two single-valued attributes a31 and a32 of which a31 is the key attribute. The relationships do not have any attributes.

If a relational model is the derived from the above ER model, then the minimum number of relations that would be generated if all the relations are in 3NF is _______.

Question No. 132

Given an instance of the STUDENTS relation as shown below:

StudentID        StudentName        StudentEmail         StudentAge          CPI        2345    Shankar      shankar@math X 9.4 1287    swati      swati@ee 19 9.5 7853    shankar      shankar@cse 19 9.4 9876    swati      swati@mech 18 9.3 8765    ganesh    ganesh@civil 19 8.7

For (StudentName,StudentAge) to be a key for this instance,the value X should NOT be equal to ________.

Question No. 14

Given the basic ER and relational models, which of the following is INCORRECT?

Question No. 82

Consider the following ER diagram

The minimum number of tables needed to represent M, N, P, R1, R2 is

Question No. 83

Consider the following ER diagram

Which of the following is a correct attribute set for one of the tables for the correct answer to the above question?