WGU C175/D426 Data Management Exam
Review UPDATED ACTUAL Exam
Questions and CORRECT Answers
Modality - CORRECT 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 - CORRECT ANSWER - Requires that ALL foreign key values must
either be fully NULL or match some primary key value.
Ways Referential Integrity can be violated - CORRECT 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 - CORRECT 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 - CORRECT ANSWER - Reference to data in one
relation is based on values in another relation.
Broad definition of data - CORRECT ANSWER - Raw facts captured on printed or digital
media.
Data - CORRECT ANSWER - Facts that are collected and stored in a database system.
Determining characteristic of unstructured data - CORRECT ANSWER - It does not follow a
data model.
,Flat files - CORRECT ANSWER - They contain no internal hierarchical organization.
Data retrieval before database management systems - CORRECT ANSWER - Sequentially
from simple files.
Primary Key - CORRECT ANSWER - An attribute or group of attributes that uniquely
identify a tuple in a relation.
Foreign Key matching - CORRECT 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 - CORRECT ANSWER - What uniquely identifies each entity in a collection
of entities but is not the primary key.
Candidate Key - CORRECT ANSWER - A set of columns in a table that can uniquely
identify any record in that table without referring to other data.
Database indexing - CORRECT ANSWER - The original data is copied to the index.
Indexes in physical database design - CORRECT ANSWER - To retrieve data DIRECTLY
using a pointer.
Index creation on a database column - CORRECT ANSWER - To optimize data retrievals.
Functional Dependency - CORRECT ANSWER - Each value of a column relates to at MOST
one value of another column.
Rules/Appearance of First Normal Form - CORRECT 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 - CORRECT 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 - CORRECT ANSWER - - All non-key columns
depend ONLY on the primary key - Tables are totally free of data redundancy.
Differences between operational and analytical databases - CORRECT ANSWER --
Volatility - Detail - Scope - History.
Volatility - CORRECT ANSWER - Database updates in real time. Operational Data is
Volatile. Analytical Data is NOT Volatile.
Detail in databases - CORRECT ANSWER - - A database that keeps record of individual
transactions; line items - Operational: Detailed - Analytical: Detailed.
Scope in databases - CORRECT ANSWER - - How far a database can reach - Operational:
incompatible - Analytical: Enterprise-Wide/Summary.
History in databases - CORRECT ANSWER - - Whether DB is current or tracks all data -
Operational: Current only - Analytical: Tracks trends.
Data warehouse refresh process - CORRECT ANSWER - 1. Extraction 2. Cleanse 3. Integrate
4. Restructure 5. Load.
Extraction in ETL - CORRECT ANSWER - Data extracted and put into staging area.
Cleanse in ETL - CORRECT ANSWER - Errors are eliminated from data; standard
abbreviations applied.
, Integrate in ETL - CORRECT ANSWER - Data is put into a uniform structure; Data
converted to uniform structure.
Restructure in ETL - CORRECT ANSWER - Data is structured in a design that is optimal for
analysis.
Load in ETL - CORRECT ANSWER - Data is loaded to the data warehouse.
Issue focused on 'Load' component of ETL - CORRECT ANSWER - Monitor refreshing
volume and frequency.
Step in ETL Process where raw data is aggregated - CORRECT ANSWER - Transformation
steps.
Data mining activities - CORRECT ANSWER - 1. Clustering & Segmentation 2.
Classification 3. Estimation 4. Prediction 5. Affinity Grouping 6. Description.
Clustering & Segmentation - CORRECT ANSWER - Taking large entity and dividing into
smaller groups of entities. Useful when unsure of what looking for.
Classification (Data Mining) - CORRECT ANSWER - Organizing data into predefined
classes.
Estimation (Data Mining) - CORRECT ANSWER - Assigning a numeric value to an object.
Prediction (Data Mining) - CORRECT ANSWER - Classifying objects according to an
expected future behavior.
Affinity Grouping - CORRECT ANSWER - Evaluating relationships between data elements
that demonstrate some kind of affinity between objects.
Review UPDATED ACTUAL Exam
Questions and CORRECT Answers
Modality - CORRECT 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 - CORRECT ANSWER - Requires that ALL foreign key values must
either be fully NULL or match some primary key value.
Ways Referential Integrity can be violated - CORRECT 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 - CORRECT 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 - CORRECT ANSWER - Reference to data in one
relation is based on values in another relation.
Broad definition of data - CORRECT ANSWER - Raw facts captured on printed or digital
media.
Data - CORRECT ANSWER - Facts that are collected and stored in a database system.
Determining characteristic of unstructured data - CORRECT ANSWER - It does not follow a
data model.
,Flat files - CORRECT ANSWER - They contain no internal hierarchical organization.
Data retrieval before database management systems - CORRECT ANSWER - Sequentially
from simple files.
Primary Key - CORRECT ANSWER - An attribute or group of attributes that uniquely
identify a tuple in a relation.
Foreign Key matching - CORRECT 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 - CORRECT ANSWER - What uniquely identifies each entity in a collection
of entities but is not the primary key.
Candidate Key - CORRECT ANSWER - A set of columns in a table that can uniquely
identify any record in that table without referring to other data.
Database indexing - CORRECT ANSWER - The original data is copied to the index.
Indexes in physical database design - CORRECT ANSWER - To retrieve data DIRECTLY
using a pointer.
Index creation on a database column - CORRECT ANSWER - To optimize data retrievals.
Functional Dependency - CORRECT ANSWER - Each value of a column relates to at MOST
one value of another column.
Rules/Appearance of First Normal Form - CORRECT 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 - CORRECT 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 - CORRECT ANSWER - - All non-key columns
depend ONLY on the primary key - Tables are totally free of data redundancy.
Differences between operational and analytical databases - CORRECT ANSWER --
Volatility - Detail - Scope - History.
Volatility - CORRECT ANSWER - Database updates in real time. Operational Data is
Volatile. Analytical Data is NOT Volatile.
Detail in databases - CORRECT ANSWER - - A database that keeps record of individual
transactions; line items - Operational: Detailed - Analytical: Detailed.
Scope in databases - CORRECT ANSWER - - How far a database can reach - Operational:
incompatible - Analytical: Enterprise-Wide/Summary.
History in databases - CORRECT ANSWER - - Whether DB is current or tracks all data -
Operational: Current only - Analytical: Tracks trends.
Data warehouse refresh process - CORRECT ANSWER - 1. Extraction 2. Cleanse 3. Integrate
4. Restructure 5. Load.
Extraction in ETL - CORRECT ANSWER - Data extracted and put into staging area.
Cleanse in ETL - CORRECT ANSWER - Errors are eliminated from data; standard
abbreviations applied.
, Integrate in ETL - CORRECT ANSWER - Data is put into a uniform structure; Data
converted to uniform structure.
Restructure in ETL - CORRECT ANSWER - Data is structured in a design that is optimal for
analysis.
Load in ETL - CORRECT ANSWER - Data is loaded to the data warehouse.
Issue focused on 'Load' component of ETL - CORRECT ANSWER - Monitor refreshing
volume and frequency.
Step in ETL Process where raw data is aggregated - CORRECT ANSWER - Transformation
steps.
Data mining activities - CORRECT ANSWER - 1. Clustering & Segmentation 2.
Classification 3. Estimation 4. Prediction 5. Affinity Grouping 6. Description.
Clustering & Segmentation - CORRECT ANSWER - Taking large entity and dividing into
smaller groups of entities. Useful when unsure of what looking for.
Classification (Data Mining) - CORRECT ANSWER - Organizing data into predefined
classes.
Estimation (Data Mining) - CORRECT ANSWER - Assigning a numeric value to an object.
Prediction (Data Mining) - CORRECT ANSWER - Classifying objects according to an
expected future behavior.
Affinity Grouping - CORRECT ANSWER - Evaluating relationships between data elements
that demonstrate some kind of affinity between objects.
