High-speed ________ communication lines use fiber-optics

Assume that transactions are executed at REPEATABLE READ. Give an example in which a phantom occurs when a transaction executes a DELETE statement to delete a set of tuples satisfying some predicate, P.

What will be an ideal response?

A linked list has the functions insertAtFront, removeFromFront, insertAtBack and removeFromBack, which perform operations on nodes exactly as their names describe. Which two functions would most naturally model the enqueue and dequeue operations, respectively, of a queue?

a. insertAtBack and removeFromBack. b. insertAtBack and removeFromFront. c. removeFromFront and insertAtFront. d. removeFromFront and insertAtBack.