DMC Data Modeling Fundamentals 2

Question 1

What is a surrogate key?

Accepted Answer

A system-generated identifier with no business meaning

Answer

A key borrowed from another table

Answer

A composite key made of multiple columns

Answer

A natural identifier from the real world

Question 2

Which of the following is a characteristic of a natural key?

Accepted Answer

It derives its value from business attributes that already exist

Answer

It is always numeric

Answer

It is generated by the database system

Answer

It never appears in reports

Question 3

What is the key difference between a strong entity and a weak entity?

Accepted Answer

A weak entity cannot be uniquely identified without referencing its parent entity

Answer

Strong entities have more attributes than weak entities

Answer

Strong entities use surrogate keys; weak entities use natural keys

Answer

Weak entities cannot have relationships

Question 4

What does the term 'optionality' refer to in a data model?

Accepted Answer

Whether a relationship participation is mandatory or optional

Answer

Whether an attribute can store NULL values

Answer

The choice between surrogate and natural keys

Answer

Optional indexes on non-key columns

Question 5

Which modeling artifact is used to document the meaning and origin of a single data element across an enterprise?

Accepted Answer

Data element definition record

Answer

Entity-Relationship Diagram

Answer

Conceptual schema

Answer

Physical table script

Question 6

In the context of DMC, what does 'domain' mean when applied to an attribute?

Accepted Answer

The set of all valid values an attribute can hold

Answer

The network domain hosting the database

Answer

The business unit that owns the data

Answer

The geographic region of data storage