WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA EXAM 2023-2024 ACTUAL EXAM 2 LATEST VERSIONS 300 QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES (100% CORRECT AND VERIFIED ANSWERS)|ALREADY GRADED A+

WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA

EXAM 2023-2024 ACTUAL EXAM 2 LATEST VERSIONS 300

QUESTIONS AND CORRECT DETAILED ANSWERS WITH

RATIONALES (100% CORRECT AND VERIFIED

ANSWERS)|ALREADY GRADED A+

VERSION A

What does modality refer to? How does it appear on ER diagram? - ANSWERRefers to the MINIMUM number of times an instance in one entity can be

associated with instance of another entity (minima)

Appears as a 0 or 1 on the relationship line, next to cardinality

Define: Referential Integrity - ANSWER- Requires that ALL foreign key values

must either be fully NULL or match some primary key value

4 Ways Referential Integrity can be violated: - ANSWER- 1. Primary key is

updated

2. Foreign key is updated

3. Row containing primary key is DELETED

4. Row containing foreign key is INSERTED

4 Actions to Correct Referential Integrity Violation: - ANSWER- 1. RESTRICT -

rejects an insert, update, or delete

2. SET NULL - sets invalid foreign keys to null

3. SET DEFAULT - sets invalid foreign keys to a default primary value

4. CASCADE - propagates primary key changes to foreign keys

What is an important aspect to referential integrity? - ANSWER- reference to data

in one relation is based on values in another relation

What is a broad definition of data? - ANSWER- Raw facts captured on printed or

digital media

What are data? - ANSWER- Facts that are collected and stored in a database

system

What is a determining characteristic of unstructured data? - ANSWER- It does not

follow a data model

What is true about flat files? - ANSWER- - They contain no internal hierarchical

organization

How were data retrieved before database management systems? - ANSWERSequentially from simple files

What is an attribute or group of attributes that uniquely identify a tuple in a

relation? - ANSWER- Primary Key

What is necessary for a primary key in one relation of a database to match with its

corresponding foreign key in another relation of the same database? - ANSWERA domain of values

What uniquely identifies each entity in a collection of entities but is not the

primary key? - ANSWER- Alternate Key

What is the term for a set of columns in a table that can uniquely identify any

record in that table without referring to other data? - ANSWER- Candidate Key

What happens to the original data in database indexing? - ANSWER- It is copied

to the index

Why are indexes created in a physical database design? - ANSWER- To retrieve

data DIRECTLY using a pointer

Why is an index created on a database column? - ANSWER- To optimize data

retrievals

Define: Functional Dependency - ANSWER- Each value of a column relates to at

MOST one value of another column

Dependence of one column on another

What term is used to describe: a value of one particular attribute associated with a

specific single value of another attribute? - ANSWER- Functional Dependency

Rules/Appearance of First Normal Form - ANSWER- - All non-key columns

depend on primary key

- Each table cell contains one value

- A table with no duplicate rows

Rules/Appearance of Second Normal Form - ANSWER- - When all non-key

columns depend on the WHOLE primary key

- Must be in 1NF

- Non-key column can not depend on just one part of a composite key - a single

primary key is automatically in 2NF

Rules/Appearance of Third Normal Form - ANSWER- - All non-key columns

depend ONLY on the primary key

- Tables are totally free of data redundancy

Define: Volatility; How it applies to Operational? Analytical? - ANSWER- -

Database updates in real time

- Operational Data is Volatile

- Analytical Data is NOT Volatile

Define: Detail; How it applies to operational and analytical DB? - ANSWER- - A

database that keeps record of individual transactions; line items

- Operational: Detailed

- Analytical: Detailed

Define: Scope; How it applies to operational and analytical DB? - ANSWER- -

How far a database can reach

- Operational: incompatible

- Analytical: Enterprise-Wide/Summary

Define: History; How it applies to operational and analytical DB? - ANSWER- -

Whether DB is current or tracks all data

- Operational: Current only

- Analytical: Tracks trends