WGU C175-D426 DATA MANAGEMENT FOUNDATIONS OA
EXAM 2025 ACTUAL EXAM 2 LATEST VERSIONS 300
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
RATIONALES CORRECT AND VERIFIED ANSWERS)
ALREADY GRADED A+
What does modality refer to? How does it appear on ER diagram? - ANSWER-
Refers 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? - ANSWER-
Sequentially 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? - ANSWER-
A 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
What are the 4 ways that operational and analytical databases differ? - ANSWER-
- Volatility
- Detail
- Scope
- History
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
Data warehouses are refreshed periodically with a 5-step process: - ANSWER- 1.
Extraction
2. Cleanse
, 3. Integrate
4. Restructure
5. Load
What happens during Extraction? (ETL) - ANSWER- Data extracted and put into
staging area
What happens during Cleanse? (ETL) - ANSWER- Errors are eliminated from
data; standard abbreviations applied
What happens during Integrate? (ETL) - ANSWER- Data is put into a uniform
structure; Data converted to uniform structure
What happens during Restructure? (ETL) - ANSWER- Data is structured in a
design that is optimal for analysis
What happens during Load? (ETL) - ANSWER- Data is loaded to the data
warehouse
What is an issue that is focused on the 'Load' component of ETL? - ANSWER-
Monitor refreshing volume and frequency
During which step in the ETL Process, is raw data aggregated? - ANSWER-
Transformation steps
What are the 6 different data mining activities? - ANSWER- 1. Clustering &
Segmentation
2. Classification
3. Estimation
4. Prediction
5. Affinity Grouping
6. Description
EXAM 2025 ACTUAL EXAM 2 LATEST VERSIONS 300
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
RATIONALES CORRECT AND VERIFIED ANSWERS)
ALREADY GRADED A+
What does modality refer to? How does it appear on ER diagram? - ANSWER-
Refers 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? - ANSWER-
Sequentially 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? - ANSWER-
A 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
What are the 4 ways that operational and analytical databases differ? - ANSWER-
- Volatility
- Detail
- Scope
- History
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
Data warehouses are refreshed periodically with a 5-step process: - ANSWER- 1.
Extraction
2. Cleanse
, 3. Integrate
4. Restructure
5. Load
What happens during Extraction? (ETL) - ANSWER- Data extracted and put into
staging area
What happens during Cleanse? (ETL) - ANSWER- Errors are eliminated from
data; standard abbreviations applied
What happens during Integrate? (ETL) - ANSWER- Data is put into a uniform
structure; Data converted to uniform structure
What happens during Restructure? (ETL) - ANSWER- Data is structured in a
design that is optimal for analysis
What happens during Load? (ETL) - ANSWER- Data is loaded to the data
warehouse
What is an issue that is focused on the 'Load' component of ETL? - ANSWER-
Monitor refreshing volume and frequency
During which step in the ETL Process, is raw data aggregated? - ANSWER-
Transformation steps
What are the 6 different data mining activities? - ANSWER- 1. Clustering &
Segmentation
2. Classification
3. Estimation
4. Prediction
5. Affinity Grouping
6. Description
