Question 1
Marks : +2 | -2
Pass Ratio : 100%
Functional dependencies that have a time associated with them during which they are valid are called as________
Explanation: Functional dependencies that have a time associated with them during which they are valid are called as temporal functional dependencies. All snapshots of the relation should satisfy the functional dependency for it to be a temporal functional dependency.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
To specify the foreign keys in relations referencing temporal data we need to specify _______
Explanation: To specify the foreign keys in relations referencing temporal data we need to specify the time interval. The time interval specification thus preserves referential integrity in the relation.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
What is unique role assumption?
Explanation: Unique role assumption means that the attribute names must have unique meaning in the database. This prevents us from using the same attribute to mean different things in different schemas.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is not a process of generating a good relational schema?
Explanation: Joining multiple relations together to form a single relation containing all the attributes is not a method for the development of good relational schema because it might violate the normal forms if it is combined.