Chapt.4 - Advanced Data Modeling

The entity ___ contains common characteristics, and the entity ___ each contains its own unique characteristics.

• instance, set

• subtype, supertype

• supertype, subtype

• subclass, superclass

Two criteria help the designer determine when to use subtypes and supertypes.

[Tick all that applies]

• some distinguishing characteristic(s)

• No unique attributes

• several common features

The attribute in the supertype entity that determines to which subtype the supertype occurrence is related.

• discriminator
• connector
• relation
• identifier

The relationship between a superclass and any one of its subclasses is called

• one-to-one

• is-a

• one-to-many

• many-to-many

___constraint means that an entity can be a member of at most one of the subclasses of the specialization.

• Overlapping
• Complete

• Disjoint
• Partial

If every EMPLOYEE must be either an HOURLY_EMPLOYEE or a SALARIED_EMPLOYEE, then this is a ___ specialization of EMPLOYEE.

• Total

• Partial

• Overlapping

• Shared

Deleting an entity from a superclass implies that

• the entity will still exist in all its subclasses
• the entity will also be deleted from all its subclasses
• the entity will be moved to a different superclass
• the entity will be marked as deleted but still exist in all its subclasses

Inserting an entity in a superclass of a total specialization implies that

• The entity will only be inserted in the superclass.
• The entity will be inserted in a subclass based on a specific condition.
• The entity will also be inserted in at least one of the subclasses.

• The entity will be inserted in a random subclass.

A specialization hierarchy has the constraint that

• allows for multiple specializations at the same level

• a subclass may have more than one parent

• each subclass has only one parent

Entity clusters are used to

• group entities based on their size.

• group entities based on their location.

• group entities based on their color.

• group similar entities together based on their attributes or characteristics.