Entity-Relationship Modeling Flashcards
7 cards from real 1Z0-006 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Entity-Relationship Modeling flashcards as text
In EER (Enhanced Entity-Relationship) modeling, 'specialization' is best defined as:
Answer: Defining subclasses of an entity type based on distinguishing characteristics
Specialization is a top-down process of defining subclasses from a superclass based on specific distinguishing features.
What is 'generalization' in EER modeling?
Answer: Combining common attributes of multiple entity types into a higher-level superclass
Generalization is a bottom-up process where shared attributes of multiple entity types are abstracted into a common superclass.
A 'disjoint' specialization constraint in EER means:
Answer: An entity instance can belong to at most one subclass at a time
A disjoint constraint (marked 'd' in EER diagrams) means the subclasses are mutually exclusive — an entity can be in only one subclass.
In EER, an 'overlapping' specialization means:
Answer: An entity instance can simultaneously belong to more than one subclass
An overlapping constraint (marked 'o') allows an entity instance to be a member of multiple subclasses at the same time.
Which of the following best describes 'total specialization'?
Answer: Every superclass instance must belong to at least one subclass
Total specialization (double line in EER) means every entity in the superclass must also be a member of at least one subclass.
An 'associative entity' (also called a gerund) is used in ER modeling to:
Answer: Treat a many-to-many relationship as an entity so it can have its own attributes and participate in other relationships
An associative entity 'reifies' a relationship, turning it into an entity that can carry its own attributes and connect to other entities.
Which mapping rule is used when converting a 1:1 relationship to relational tables?
Answer: Add the primary key of either participating entity as a foreign key in the other entity's table
For a 1:1 relationship, the standard approach is to add the primary key of one entity as a foreign key in the other entity's table, preferably on the total-participation side.