Consider the following relational schema:
Employee (empId, empName, empDept)
Customer (custId, CustName, salesRepId, rating)
SalesRepId is a foreign key referring to empId of the employee relation. Assume that each employee makes a sale to at least one customer. What does the following query return?
FROM employee E
WHERE NOT EXISTS (SELECT custId
FROM customer C
WHERE C. salesRepId = E. empId
AND C. rating < > ‘GOOD’)
An operating system uses the Banker’s algorithm for deadlock avoidance when managing the allocation of three resource types X, Y, and Z to three processes P0, P1, and P2. The table given below presents the current system state. Here, the Allocation matrix shows the current number of resources of each type allocated to each process and the Max matrix shows the maximum number of resources of each type required by each process during its execution.
There are 3 units of type X, 2 units of type Y and 2 units of type Z still available. The system is currently in a safe state. Consider the following independent requests for additional resources in the current state: REQ1: P0 requests 0 units of X, 0 units of Y and 2 units of Z REQ2: P1 requests 2 units of X, 0 units of Y and 0 units of Z Which one of the following is TRUE?
How many tuples does the result of the following SQL query contain?
SELECT A.Id FROM A WHERE A.Age > ALL (SELECT B.Age FROM B WHERE B.Name = ‘Arun’)