Composition is a stronger form of which of the following?

An abstract class is which of the following?

• [A] A class that has direct instances, but whose descendants may have direct instances.
• [B] A class that has no direct instances, but whose descendants may have direct instances.
• [C] A class that has direct instances, but whose descendants may not have direct instances.
• [D] A class that has no direct instances, but whose descendants may not have direct instances

The level of data abstraction which describes how the data is actually stored is?

• [A] Physical level
• [B] Conceptual level
• [C] Storage Level
• [D] File level

The ability to modify the conceptual schema without causing any change to the application program is known as :

• [A] Physical data independence
• [B] Logical data independence
• [C] External data independence
• [D] Static data

An intrusion detection system does not perform which of the following?

• [A] Tries to identify attempts to hack into a computer system.
• [B] May monitor packets passing over the network.
• [C] May transmit message packets to the correct destination.
• [D] Set up deception systems that attempt to trap hackers.

An association of several structure of a data base can be expressed graphically by?

• [A] Tuple
• [B] Record
• [C] Relationship
• [D] Field