WGU D426 DATA MANAGEMENT FOUNDATIONS OA FINAL
EXAM 2024/2025 QUESTIONS AND VERIFIED CORRECT
ANSWERS/ ALREADY GRADED A++
Query Processor - ANSWER Interprets queries. Compiles queries into low-
level instructions for the storage engine. Creates a plan to modify the
database or retrieve data, and returns query results to the application.
Query Optimization - ANSWER Ensures the most efficient instructions are
executed on the data by the query processor.
Storage Manager/Engine - ANSWER Translates query processor
instructions into low-level file system commands. Uses indexes to quickly
locate data.
Transaction Manager - ANSWER Ensures proper execution of
transactions. Prevents conflicts between concurrent transactions and
restores the database to a consistent state in case of failure.
CRUD - ANSWER Create, Read, Update, Delete. Operations:
Insert(create), Select(read), Update, Delete.
Analysis/Conceptual Design - ANSWER Specifies database requirements
without specific database system considerations. Represents requirements
as entities, relationships, and attributes.
Logical Design - ANSWER Implements database requirements in a specific
system. Converts entities, relationships, and attributes into tables, keys,
and columns. Also known as schema.
Physical Design - ANSWER Adds indexes and specifies table organization
on storage media. Affects query processing speed but not query results.
Data Independence - ANSWER Physical design does not affect query
results.
API (Application Programming Interface) - ANSWER Library of
procedures/classes linking a programming language to a database.
Simplifies SQL usage.
,MySQL Command-Line Client - ANSWER A text interface included in the
MySQL Server download.
Set - ANSWER An unordered collection of elements enclosed in braces {}.
Tuple - ANSWER An ordered collection of elements enclosed in
parentheses ().
Business Rules - ANSWER Based on business policy and specific to a
particular database. Relational rules govern data in all relational databases.
DDL - ANSWER Data Definition Language (DDL) defines the structure of
the database. Controls tables. Includes CREATE, DROP, ALTER,
TRUNCATE, RENAME.
DQL - ANSWER Data Query Language (DQL) retrieves data from the
database. Uses SELECT statement.
DML - ANSWER Data Manipulation Language (DML) manipulates data
stored in a database. Adds, modifies, and deletes data. Uses INSERT,
UPDATE, DELETE statements.
DCL - ANSWER Data Control Language (DCL) controls database user
access. Used to create user accounts, manage permissions, and access.
DTL - ANSWER Data Transaction Language (DTL) manages database
transactions. Can rollback database changes.
UPDATE - ANSWER The UPDATE statement modifies existing rows in a
table. It uses the SET clause to specify the new column values.
DELETE Statement - ANSWER The DELETE statement removes existing
rows from a table. It is followed by the FROM keyword and the table name.
Primary Key - ANSWER A primary key is a column or group of columns
used to uniquely identify a row. It is typically the first column in a table. It is
simple if it consists of a single column.
,Composite Primary Key - ANSWER A composite primary key is made up of
multiple columns.
Foreign Key - ANSWER A foreign key is a column or group of columns that
references a primary key in another table.
Referential Integrity - ANSWER Referential integrity ensures that foreign
key values are either NULL or match a value in the referenced primary key.
LIKE Operator - ANSWER The LIKE operator in a WHERE clause matches
text against a pattern using % and _ as wildcard characters.
INNER JOIN - ANSWER An INNER JOIN selects rows with matching
values in both the left and right tables.
FULL JOIN - ANSWER A FULL JOIN selects all rows from both left and
right tables, regardless of matches.
LEFT JOIN - ANSWER A LEFT JOIN selects all rows from the left table
and matching rows from the right table.
RIGHT JOIN - ANSWER A RIGHT JOIN selects all rows from the right
table and matching rows from the left table.
Outer Join - ANSWER An OUTER JOIN selects unmatched rows, including
left, right, and full joins.
Union - ANSWER The UNION keyword combines the results of two queries
into a single result set.
Equijoin - ANSWER An equijoin compares columns of two tables using the
= operator.
Non-Equijoin - ANSWER A non-equijoin compares columns using
operators other than =, like < and >.
Self-Join - ANSWER A self-join joins a table to itself.
Cross-Join - ANSWER A cross-join combines two tables without comparing
columns.
, Subquery - ANSWER A subquery, also known as a nested query, is a
query within another SQL query.
Correlated Subquery - ANSWER A correlated subquery references a
column from the outer query in its WHERE clause.
Alias - ANSWER An alias is a temporary name assigned to a column or
table.
Materialized View - ANSWER A materialized view stores data at all times
and must be refreshed when the base table changes.
With Check Option - ANSWER Specifies that the database rejects inserts
and updates not satisfying the view query WHERE clause
Entity-Relationship Model - ANSWER A high-level representation of data
requirements, ignoring implementation details
Objects in an Entity-Relationship Model - ANSWER Entity - person, place,
product, concept, or activity.
Relationship - statement about two entities.
Attribute - descriptive property of an entity
Entity-Relationship Diagram (ER Diagram) - ANSWER Schematic picture of
entities, relationships, and attributes. Entities are drawn as rectangles
Entity Type and Instance - ANSWER Entity type is a set of things (e.g., all
employees in a company).
Entity instance is an individual thing (e.g., the employee Sam Snead)
Relationship Type and Instance - ANSWER Relationship type is a set of
related things (e.g., Employee-Manages-Department).
Relationship instance is a statement about entity instances (e.g., 'Maria
Rodriguez manages Sales')
Reflexive Relationship - ANSWER Relates an entity to itself
Attribute Type and Instance - ANSWER Attribute type is a set of values
(e.g., all employee salaries).
EXAM 2024/2025 QUESTIONS AND VERIFIED CORRECT
ANSWERS/ ALREADY GRADED A++
Query Processor - ANSWER Interprets queries. Compiles queries into low-
level instructions for the storage engine. Creates a plan to modify the
database or retrieve data, and returns query results to the application.
Query Optimization - ANSWER Ensures the most efficient instructions are
executed on the data by the query processor.
Storage Manager/Engine - ANSWER Translates query processor
instructions into low-level file system commands. Uses indexes to quickly
locate data.
Transaction Manager - ANSWER Ensures proper execution of
transactions. Prevents conflicts between concurrent transactions and
restores the database to a consistent state in case of failure.
CRUD - ANSWER Create, Read, Update, Delete. Operations:
Insert(create), Select(read), Update, Delete.
Analysis/Conceptual Design - ANSWER Specifies database requirements
without specific database system considerations. Represents requirements
as entities, relationships, and attributes.
Logical Design - ANSWER Implements database requirements in a specific
system. Converts entities, relationships, and attributes into tables, keys,
and columns. Also known as schema.
Physical Design - ANSWER Adds indexes and specifies table organization
on storage media. Affects query processing speed but not query results.
Data Independence - ANSWER Physical design does not affect query
results.
API (Application Programming Interface) - ANSWER Library of
procedures/classes linking a programming language to a database.
Simplifies SQL usage.
,MySQL Command-Line Client - ANSWER A text interface included in the
MySQL Server download.
Set - ANSWER An unordered collection of elements enclosed in braces {}.
Tuple - ANSWER An ordered collection of elements enclosed in
parentheses ().
Business Rules - ANSWER Based on business policy and specific to a
particular database. Relational rules govern data in all relational databases.
DDL - ANSWER Data Definition Language (DDL) defines the structure of
the database. Controls tables. Includes CREATE, DROP, ALTER,
TRUNCATE, RENAME.
DQL - ANSWER Data Query Language (DQL) retrieves data from the
database. Uses SELECT statement.
DML - ANSWER Data Manipulation Language (DML) manipulates data
stored in a database. Adds, modifies, and deletes data. Uses INSERT,
UPDATE, DELETE statements.
DCL - ANSWER Data Control Language (DCL) controls database user
access. Used to create user accounts, manage permissions, and access.
DTL - ANSWER Data Transaction Language (DTL) manages database
transactions. Can rollback database changes.
UPDATE - ANSWER The UPDATE statement modifies existing rows in a
table. It uses the SET clause to specify the new column values.
DELETE Statement - ANSWER The DELETE statement removes existing
rows from a table. It is followed by the FROM keyword and the table name.
Primary Key - ANSWER A primary key is a column or group of columns
used to uniquely identify a row. It is typically the first column in a table. It is
simple if it consists of a single column.
,Composite Primary Key - ANSWER A composite primary key is made up of
multiple columns.
Foreign Key - ANSWER A foreign key is a column or group of columns that
references a primary key in another table.
Referential Integrity - ANSWER Referential integrity ensures that foreign
key values are either NULL or match a value in the referenced primary key.
LIKE Operator - ANSWER The LIKE operator in a WHERE clause matches
text against a pattern using % and _ as wildcard characters.
INNER JOIN - ANSWER An INNER JOIN selects rows with matching
values in both the left and right tables.
FULL JOIN - ANSWER A FULL JOIN selects all rows from both left and
right tables, regardless of matches.
LEFT JOIN - ANSWER A LEFT JOIN selects all rows from the left table
and matching rows from the right table.
RIGHT JOIN - ANSWER A RIGHT JOIN selects all rows from the right
table and matching rows from the left table.
Outer Join - ANSWER An OUTER JOIN selects unmatched rows, including
left, right, and full joins.
Union - ANSWER The UNION keyword combines the results of two queries
into a single result set.
Equijoin - ANSWER An equijoin compares columns of two tables using the
= operator.
Non-Equijoin - ANSWER A non-equijoin compares columns using
operators other than =, like < and >.
Self-Join - ANSWER A self-join joins a table to itself.
Cross-Join - ANSWER A cross-join combines two tables without comparing
columns.
, Subquery - ANSWER A subquery, also known as a nested query, is a
query within another SQL query.
Correlated Subquery - ANSWER A correlated subquery references a
column from the outer query in its WHERE clause.
Alias - ANSWER An alias is a temporary name assigned to a column or
table.
Materialized View - ANSWER A materialized view stores data at all times
and must be refreshed when the base table changes.
With Check Option - ANSWER Specifies that the database rejects inserts
and updates not satisfying the view query WHERE clause
Entity-Relationship Model - ANSWER A high-level representation of data
requirements, ignoring implementation details
Objects in an Entity-Relationship Model - ANSWER Entity - person, place,
product, concept, or activity.
Relationship - statement about two entities.
Attribute - descriptive property of an entity
Entity-Relationship Diagram (ER Diagram) - ANSWER Schematic picture of
entities, relationships, and attributes. Entities are drawn as rectangles
Entity Type and Instance - ANSWER Entity type is a set of things (e.g., all
employees in a company).
Entity instance is an individual thing (e.g., the employee Sam Snead)
Relationship Type and Instance - ANSWER Relationship type is a set of
related things (e.g., Employee-Manages-Department).
Relationship instance is a statement about entity instances (e.g., 'Maria
Rodriguez manages Sales')
Reflexive Relationship - ANSWER Relates an entity to itself
Attribute Type and Instance - ANSWER Attribute type is a set of values
(e.g., all employee salaries).
