Database-Management-System
October 3, 2023JNU PhD CS 2019
October 3, 2023GATE 2012
| Question 14 |
Given the basic ER and relational models, which of the following is INCORRECT?
| An attribute of an entity can have more than one value | |
| An attribute of an entity can be composite | |
| In a row of a relational table, an attribute can have more than one value | |
| In a row of a relational table, an attribute can have exactly one value or a NULL value |
Question 14 Explanation:
Option (A): In ER-model, multivalued attribute of an entity can have more than one value.
Option (B): In ER model, the attribute which can be further broken down into some other attributes is called composite attribute.
Option (C): In Relational model, the intersection of one row and column should contain only one value. So, option (C) is INCORRECT.
Option (D): In Relational model, the intersection of one row and column should contain either exactly one value or NULL.
Option (B): In ER model, the attribute which can be further broken down into some other attributes is called composite attribute.
Option (C): In Relational model, the intersection of one row and column should contain only one value. So, option (C) is INCORRECT.
Option (D): In Relational model, the intersection of one row and column should contain either exactly one value or NULL.
Correct Answer: C
Question 14 Explanation:
Option (A): In ER-model, multivalued attribute of an entity can have more than one value.
Option (B): In ER model, the attribute which can be further broken down into some other attributes is called composite attribute.
Option (C): In Relational model, the intersection of one row and column should contain only one value. So, option (C) is INCORRECT.
Option (D): In Relational model, the intersection of one row and column should contain either exactly one value or NULL.
Option (B): In ER model, the attribute which can be further broken down into some other attributes is called composite attribute.
Option (C): In Relational model, the intersection of one row and column should contain only one value. So, option (C) is INCORRECT.
Option (D): In Relational model, the intersection of one row and column should contain either exactly one value or NULL.