WGU C175/D426 Data Management Exam
Review Practice Questions And Verified
Answers 2024/2025 Update
Modality - 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.
Referential Integrity - ANSWER>>>Requires that ALL foreign key values
must either be fully NULL or match some primary key value.
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.
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.
Important aspect of Referential Integrity - ANSWER>>>Reference to data
in one relation is based on values in another relation.
Broad definition of data - ANSWER>>>Raw facts captured on printed or
digital media.
Data - ANSWER>>>Facts that are collected and stored in a database
system.
Determining characteristic of unstructured data - ANSWER>>>It does not
follow a data model.
Flat files - ANSWER>>>They contain no internal hierarchical organization.
Primary Key - ANSWER>>>An attribute or group of attributes that uniquely
identify a tuple in a relation.
,Data retrieval before database management systems -
ANSWER>>>Sequentially from simple files.
Foreign Key matching - ANSWER>>>A domain of values 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.
Alternate Key - ANSWER>>>What uniquely identifies each entity in a
collection of entities but is not the primary key.
Candidate Key - ANSWER>>>A set of columns in a table that can uniquely
identify any record in that table without referring to other data.
Database indexing - ANSWER>>>The original data is copied to the index.
Indexes in physical database design - ANSWER>>>To retrieve data
DIRECTLY using a pointer.
Index creation on a database column - ANSWER>>>To optimize data
retrievals.
Differences between operational and analytical databases - ANSWER>>>-
Volatility - Detail - Scope - History.
Functional Dependency - ANSWER>>>Each value of a column relates to
at MOST one value of another column.
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.
Volatility - ANSWER>>>Database updates in real time. Operational Data is
Volatile. Analytical Data is NOT Volatile.
Detail in databases - ANSWER>>>- A database that keeps record of
individual transactions; line items - Operational: Detailed - Analytical:
Detailed.
Scope in databases - ANSWER>>>- How far a database can reach -
Operational: incompatible - Analytical: Enterprise-Wide/Summary.
History in databases - ANSWER>>>- Whether DB is current or tracks all
data - Operational: Current only - Analytical: Tracks trends.
Data warehouse refresh process - ANSWER>>>1. Extraction 2. Cleanse 3.
Integrate 4. Restructure 5. Load.
Extraction in ETL - ANSWER>>>Data extracted and put into staging area.
Cleanse in ETL - ANSWER>>>Errors are eliminated from data; standard
abbreviations applied.
Integrate in ETL - ANSWER>>>Data is put into a uniform structure; Data
converted to uniform structure.
Restructure in ETL - ANSWER>>>Data is structured in a design that is
optimal for analysis.
Load in ETL - ANSWER>>>Data is loaded to the data warehouse.
Issue focused on 'Load' component of ETL - ANSWER>>>Monitor
refreshing volume and frequency.
Step in ETL Process where raw data is aggregated -
ANSWER>>>Transformation steps.
Review Practice Questions And Verified
Answers 2024/2025 Update
Modality - 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.
Referential Integrity - ANSWER>>>Requires that ALL foreign key values
must either be fully NULL or match some primary key value.
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.
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.
Important aspect of Referential Integrity - ANSWER>>>Reference to data
in one relation is based on values in another relation.
Broad definition of data - ANSWER>>>Raw facts captured on printed or
digital media.
Data - ANSWER>>>Facts that are collected and stored in a database
system.
Determining characteristic of unstructured data - ANSWER>>>It does not
follow a data model.
Flat files - ANSWER>>>They contain no internal hierarchical organization.
Primary Key - ANSWER>>>An attribute or group of attributes that uniquely
identify a tuple in a relation.
,Data retrieval before database management systems -
ANSWER>>>Sequentially from simple files.
Foreign Key matching - ANSWER>>>A domain of values 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.
Alternate Key - ANSWER>>>What uniquely identifies each entity in a
collection of entities but is not the primary key.
Candidate Key - ANSWER>>>A set of columns in a table that can uniquely
identify any record in that table without referring to other data.
Database indexing - ANSWER>>>The original data is copied to the index.
Indexes in physical database design - ANSWER>>>To retrieve data
DIRECTLY using a pointer.
Index creation on a database column - ANSWER>>>To optimize data
retrievals.
Differences between operational and analytical databases - ANSWER>>>-
Volatility - Detail - Scope - History.
Functional Dependency - ANSWER>>>Each value of a column relates to
at MOST one value of another column.
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.
Volatility - ANSWER>>>Database updates in real time. Operational Data is
Volatile. Analytical Data is NOT Volatile.
Detail in databases - ANSWER>>>- A database that keeps record of
individual transactions; line items - Operational: Detailed - Analytical:
Detailed.
Scope in databases - ANSWER>>>- How far a database can reach -
Operational: incompatible - Analytical: Enterprise-Wide/Summary.
History in databases - ANSWER>>>- Whether DB is current or tracks all
data - Operational: Current only - Analytical: Tracks trends.
Data warehouse refresh process - ANSWER>>>1. Extraction 2. Cleanse 3.
Integrate 4. Restructure 5. Load.
Extraction in ETL - ANSWER>>>Data extracted and put into staging area.
Cleanse in ETL - ANSWER>>>Errors are eliminated from data; standard
abbreviations applied.
Integrate in ETL - ANSWER>>>Data is put into a uniform structure; Data
converted to uniform structure.
Restructure in ETL - ANSWER>>>Data is structured in a design that is
optimal for analysis.
Load in ETL - ANSWER>>>Data is loaded to the data warehouse.
Issue focused on 'Load' component of ETL - ANSWER>>>Monitor
refreshing volume and frequency.
Step in ETL Process where raw data is aggregated -
ANSWER>>>Transformation steps.
