WGU D426 V2 2026/2027 ACTUAL
QUESTIONS WITH VERIFIED
ANSWERS.
A column, or group of columns, used to identify a row.
Primary Key
Rejects an insert, update, or delete that violates referential
integrity.
RESTRICT
A rule that governs allowable values in a database based
on relational and business rules and implemented with
special keywords.
Constraint
Specifies an expression on one or more columns of a
table. Violated when the expression is false and satisfied
when the expression is true or null.
Check
The LIKE operator performs case-insensitive pattern
matching by default or case-sensitive pattern matching if
followed by this keyword.
BINARY
Used with GROUP BY to filter results.
HAVING
Combines two query results into one table.
,UNION
Which operator is considered an equijoin?
=
_______________ is when a subquery's WHERE clause
references a column from the outer query.
Correlated
Replacing a subquery with an equivalent join is called
what?
Flattening
The table specified in the view query's FROM clause.
Base Table
Converts a SQL query into a sequence of low-level
database actions, called the query execution plan, which
specifies precisely how to process a SQL statement.
Query Optimizer
A high-level representation of data requirements, ignoring
implementation details.
Entity-Relationship Model
A schematic picture of entities, relationships, and
attributes.
ER Diagram
Relates an entity to itself
Reflexive Relationship
Develops an entity-relationship model capturing data
requirements while ignoring implementation details.
Analysis
, Refers to the maxima and minima of relationships and
attributes.
Cardinality
Unique, singular, and required.
Identifying Attribute
A group of related entities from a complex model.
Subject Area
Created by a database designer when no suitable single-
column or composite primary key exists.
Artificial Key
Column A ______________________________ Column B
means that each B value is related to at most one A value.
Depends On
Rules for designing tables with less redundancy.
Normal Forms
The speed at which data is read or written, following initial
access.
Transfer Rate
Memory that is lost when disconnected from power.
Volatile Memory
The primary memory used when computer programs
execute. aka: main memory
Random-Access Memory
AKA: Solid State Drive. Less expensive and higher
capacity than main memory. Groups data in pages, usually
between 2 kb and 16 kb per page.
QUESTIONS WITH VERIFIED
ANSWERS.
A column, or group of columns, used to identify a row.
Primary Key
Rejects an insert, update, or delete that violates referential
integrity.
RESTRICT
A rule that governs allowable values in a database based
on relational and business rules and implemented with
special keywords.
Constraint
Specifies an expression on one or more columns of a
table. Violated when the expression is false and satisfied
when the expression is true or null.
Check
The LIKE operator performs case-insensitive pattern
matching by default or case-sensitive pattern matching if
followed by this keyword.
BINARY
Used with GROUP BY to filter results.
HAVING
Combines two query results into one table.
,UNION
Which operator is considered an equijoin?
=
_______________ is when a subquery's WHERE clause
references a column from the outer query.
Correlated
Replacing a subquery with an equivalent join is called
what?
Flattening
The table specified in the view query's FROM clause.
Base Table
Converts a SQL query into a sequence of low-level
database actions, called the query execution plan, which
specifies precisely how to process a SQL statement.
Query Optimizer
A high-level representation of data requirements, ignoring
implementation details.
Entity-Relationship Model
A schematic picture of entities, relationships, and
attributes.
ER Diagram
Relates an entity to itself
Reflexive Relationship
Develops an entity-relationship model capturing data
requirements while ignoring implementation details.
Analysis
, Refers to the maxima and minima of relationships and
attributes.
Cardinality
Unique, singular, and required.
Identifying Attribute
A group of related entities from a complex model.
Subject Area
Created by a database designer when no suitable single-
column or composite primary key exists.
Artificial Key
Column A ______________________________ Column B
means that each B value is related to at most one A value.
Depends On
Rules for designing tables with less redundancy.
Normal Forms
The speed at which data is read or written, following initial
access.
Transfer Rate
Memory that is lost when disconnected from power.
Volatile Memory
The primary memory used when computer programs
execute. aka: main memory
Random-Access Memory
AKA: Solid State Drive. Less expensive and higher
capacity than main memory. Groups data in pages, usually
between 2 kb and 16 kb per page.
