Question
The average age of a man and his two children is 15
years and the average age of man's wife and the same children is 13 years. If the age of man is 31 years, the age of his wife is (in years):Solution
Let the age of two children and wife be x, y and z. ATQ: 31 + x + y = 45 x + y = 14---------(1) Now, x + y + z = 39---------(2) Now, we know that x + y = 14 => x + y + z = 39 => 14 + z = 39 => z = 25 Therefore, age of wife = 25 years
Which of the following commands are used to put a restriction on the number of rows returned from a query?
Distributed transactions typically use which protocol for atomicity?
Which type of join returns only matching records from both tables?
A `FOREIGN KEY` constraint is used to:
In two-phase locking, a transaction releases its locks:
Bitmap indexes are most efficient when:
What is a primary key in a relational database?
Which normal form eliminates repeating groups by putting them into separate tables and connecting them through foreign keys?
In a relational schema, which normal form eliminates transitive dependencies (i.e., non-prime attribute depends on another non-prime attribute)?
A transaction that reads a value then later sees a different value because another transaction updated and committed in between experiences which anomaly?
Relevant for Exams:
