WGU D427 - Database Management Applications | COMPLETE AND
DETAILED QUESTIONS AND ANSWERS | REAL EXAM QNA | 2025
LATEST UPDATED 100% RATED CORRECT | 100% VERFIED |
ALREADY GRADED A+|GUARANTEED TO PASS!!
What is a subquery - (answer)A query within another SQL query.
What is an alias in SQL - (answer)A temporary name assigned to a column or table, created with
the AS keyword.
What is a materialized view - (answer)A view for which data is stored at all times and must be
refreshed when the base table changes.
What does the WITH CHECK OPTION clause do - (answer)Ensures that inserts and updates in a
view satisfy the view's WHERE clause.
What is an entity in entity-relationship modeling - (answer)A person, place, product, concept, or
activity.
What is a relationship in entity-relationship modeling - (answer)A statement about two entities.
What is an attribute in entity-relationship modeling - (answer)A descriptive property of an entity.
What is a reflexive relationship - (answer)A relationship that relates an entity to itself.
What is an entity-relationship diagram (ER diagram) - (answer)A schematic picture of entities,
relationships, and attributes, where entities are drawn as rectangles.
,What is an entity type - (answer)A set of things, such as all employees in a company.
What is a relationship type - (answer)A set of related things, such as employee-manages-
department pairs.
What is an attribute type - (answer)A set of values, such as all employee salaries.
What is an entity instance - (answer)An individual thing, such as the employee Sam Snead.
What is a relationship instance - (answer)A specific statement about entity instances, such as
"Maria Rodriguez manages Sales."
What is an attribute instance - (answer)An individual value, such as a salary of $35,000.
What is cardinality in entity-relationship modeling - (answer)The maxima and minima of
relationships and attributes.
What is a subtype entity - (answer)A subset of another entity type, called the supertype entity.
What is a supertype entity - (answer)An entity that has one or more subtype entities, such as
"vehicle" with subtypes like "car" and "truck."
What is an IsA relationship - (answer)The identifying relationship between a supertype and its
subtypes.
What is a partition in entity-relationship modeling - (answer)A group of mutually exclusive
subtype entities within a supertype entity.
,What is crow's foot notation - (answer)A convention for depicting cardinality in ER diagrams,
using symbols like circles, short lines, and three short lines (a crow's foot).
What is an intangible entity - (answer)An entity documented in the data model but not tracked
with data in the database.
What are the characteristics of a primary key - (answer)A primary key should be stable, simple,
and meaningless.
What is an artificial key - (answer)A single-column primary key created by the database designer
when no suitable primary key exists.
What is functional dependence - (answer)The dependence of one column on another.
What is redundancy in databases - (answer)The repetition of related values in a table.
What is a candidate key - (answer)A simple or composite column that is unique and minimal,
with all columns necessary for uniqueness.
What is a non-key column - (answer)A column that is not contained in a candidate key.
What is third normal form - (answer)A table is in third normal form if, whenever a non-key
column A depends on column B, then B is unique.
What is Boyce-Codd normal form - (answer)A stricter form of third normal form where column
B must be unique regardless of whether it is a candidate key.
What is a trivial dependency - (answer)When the columns of A are a subset of the columns of B,
A always depends on B.
, What is normalization - (answer)The process of eliminating redundancy by decomposing a table
into two or more tables in higher normal form.
What is denormalization - (answer)The intentional introduction of redundancy by merging
tables.
What is a heap table - (answer)A table where no order is imposed on rows, optimizing insert
operations.
What is a sorted table - (answer)A table where rows are physically ordered by a specified sort
column.
What is a hash table - (answer)A table where rows are assigned to buckets, optimizing search and
retrieval.
What is a table cluster - (answer)A storage structure that interleaves rows of two or more tables
in the same storage area.
What is a table scan - (answer)A database operation that reads table blocks directly without using
an index.
What is an index scan - (answer)A database operation that reads index blocks sequentially to
locate the needed table blocks.
What is a hit ratio (filter factor - (answer)selectivity), The percentage of table rows selected by a
query.
What is a binary search - (answer)A search method where the database repeatedly splits the
index in two until the search value is found.
DETAILED QUESTIONS AND ANSWERS | REAL EXAM QNA | 2025
LATEST UPDATED 100% RATED CORRECT | 100% VERFIED |
ALREADY GRADED A+|GUARANTEED TO PASS!!
What is a subquery - (answer)A query within another SQL query.
What is an alias in SQL - (answer)A temporary name assigned to a column or table, created with
the AS keyword.
What is a materialized view - (answer)A view for which data is stored at all times and must be
refreshed when the base table changes.
What does the WITH CHECK OPTION clause do - (answer)Ensures that inserts and updates in a
view satisfy the view's WHERE clause.
What is an entity in entity-relationship modeling - (answer)A person, place, product, concept, or
activity.
What is a relationship in entity-relationship modeling - (answer)A statement about two entities.
What is an attribute in entity-relationship modeling - (answer)A descriptive property of an entity.
What is a reflexive relationship - (answer)A relationship that relates an entity to itself.
What is an entity-relationship diagram (ER diagram) - (answer)A schematic picture of entities,
relationships, and attributes, where entities are drawn as rectangles.
,What is an entity type - (answer)A set of things, such as all employees in a company.
What is a relationship type - (answer)A set of related things, such as employee-manages-
department pairs.
What is an attribute type - (answer)A set of values, such as all employee salaries.
What is an entity instance - (answer)An individual thing, such as the employee Sam Snead.
What is a relationship instance - (answer)A specific statement about entity instances, such as
"Maria Rodriguez manages Sales."
What is an attribute instance - (answer)An individual value, such as a salary of $35,000.
What is cardinality in entity-relationship modeling - (answer)The maxima and minima of
relationships and attributes.
What is a subtype entity - (answer)A subset of another entity type, called the supertype entity.
What is a supertype entity - (answer)An entity that has one or more subtype entities, such as
"vehicle" with subtypes like "car" and "truck."
What is an IsA relationship - (answer)The identifying relationship between a supertype and its
subtypes.
What is a partition in entity-relationship modeling - (answer)A group of mutually exclusive
subtype entities within a supertype entity.
,What is crow's foot notation - (answer)A convention for depicting cardinality in ER diagrams,
using symbols like circles, short lines, and three short lines (a crow's foot).
What is an intangible entity - (answer)An entity documented in the data model but not tracked
with data in the database.
What are the characteristics of a primary key - (answer)A primary key should be stable, simple,
and meaningless.
What is an artificial key - (answer)A single-column primary key created by the database designer
when no suitable primary key exists.
What is functional dependence - (answer)The dependence of one column on another.
What is redundancy in databases - (answer)The repetition of related values in a table.
What is a candidate key - (answer)A simple or composite column that is unique and minimal,
with all columns necessary for uniqueness.
What is a non-key column - (answer)A column that is not contained in a candidate key.
What is third normal form - (answer)A table is in third normal form if, whenever a non-key
column A depends on column B, then B is unique.
What is Boyce-Codd normal form - (answer)A stricter form of third normal form where column
B must be unique regardless of whether it is a candidate key.
What is a trivial dependency - (answer)When the columns of A are a subset of the columns of B,
A always depends on B.
, What is normalization - (answer)The process of eliminating redundancy by decomposing a table
into two or more tables in higher normal form.
What is denormalization - (answer)The intentional introduction of redundancy by merging
tables.
What is a heap table - (answer)A table where no order is imposed on rows, optimizing insert
operations.
What is a sorted table - (answer)A table where rows are physically ordered by a specified sort
column.
What is a hash table - (answer)A table where rows are assigned to buckets, optimizing search and
retrieval.
What is a table cluster - (answer)A storage structure that interleaves rows of two or more tables
in the same storage area.
What is a table scan - (answer)A database operation that reads table blocks directly without using
an index.
What is an index scan - (answer)A database operation that reads index blocks sequentially to
locate the needed table blocks.
What is a hit ratio (filter factor - (answer)selectivity), The percentage of table rows selected by a
query.
What is a binary search - (answer)A search method where the database repeatedly splits the
index in two until the search value is found.
