D426 WGU EXAM ASSESSMENT NEWEST 2024 TEST BANK
ACTUAL EXAM 300 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
What is a subquery - CORRECT ANSWER A query within another SQL
query.
What is an alias in SQL - CORRECT ANSWER A temporary name
assigned to a column or table, created with the AS keyword.
What is a materialized view - CORRECT 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 - CORRECT ANSWER
Ensures that inserts and updates in a view satisfy the view's WHERE
clause.
What is an entity in entity-relationship modeling - CORRECT ANSWER
A person, place, product, concept, or activity.
What is a relationship in entity-relationship modeling - CORRECT
ANSWER A statement about two entities.
What is an attribute in entity-relationship modeling - CORRECT
ANSWER A descriptive property of an entity.
What is a reflexive relationship - CORRECT ANSWER A relationship
that relates an entity to itself.
What is an entity-relationship diagram (ER diagram) - CORRECT
ANSWER A schematic picture of entities, relationships, and
attributes, where entities are drawn as rectangles.
What is an entity type - CORRECT ANSWER A set of things, such as
all employees in a company.
,What is a relationship type - CORRECT ANSWER A set of related
things, such as employee-manages-department pairs.
What is an attribute type - CORRECT ANSWER A set of values, such
as all employee salaries.
What is an entity instance - CORRECT ANSWER An individual thing,
such as the employee Sam Snead.
What is a relationship instance - CORRECT ANSWER A specific
statement about entity instances, such as "Maria Rodriguez manages
Sales."
What is an attribute instance - CORRECT ANSWER An individual
value, such as a salary of $35,000.
What is cardinality in entity-relationship modeling - CORRECT
ANSWER The maxima and minima of relationships and attributes.
What is a subtype entity - CORRECT ANSWER A subset of another
entity type, called the supertype entity.
What is a supertype entity - CORRECT ANSWER An entity that has
one or more subtype entities, such as "vehicle" with subtypes like
"car" and "truck."
What is an IsA relationship - CORRECT ANSWER The identifying
relationship between a supertype and its subtypes.
What is a partition in entity-relationship modeling - CORRECT ANSWER
A group of mutually exclusive subtype entities within a supertype
entity.
What is crow's foot notation - CORRECT 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 - CORRECT ANSWER An entity
documented in the data model but not tracked with data in the
database.
What are the characteristics of a primary key - CORRECT ANSWER A
primary key should be stable, simple, and meaningless.
What is an artificial key - CORRECT ANSWER A single-column
primary key created by the database designer when no suitable
primary key exists.
What is functional dependence - CORRECT ANSWER The
dependence of one column on another.
What is redundancy in databases - CORRECT ANSWER The
repetition of related values in a table.
What is a candidate key - CORRECT ANSWER A simple or composite
column that is unique and minimal, with all columns necessary for
uniqueness.
What is a non-key column - CORRECT ANSWER A column that is not
contained in a candidate key.
What is third normal form - CORRECT 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 - CORRECT 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 - CORRECT ANSWER When the columns
of A are a subset of the columns of B, A always depends on B.
What is normalization - CORRECT ANSWER The process of
eliminating redundancy by decomposing a table into two or more
tables in higher normal form.
, What is denormalization - CORRECT ANSWER The intentional
introduction of redundancy by merging tables.
What is a heap table - CORRECT ANSWER A table where no order is
imposed on rows, optimizing insert operations.
What is a sorted table - CORRECT ANSWER A table where rows are
physically ordered by a specified sort column.
What is a hash table - CORRECT ANSWER A table where rows are
assigned to buckets, optimizing search and retrieval.
What is a table cluster - CORRECT ANSWER A storage structure that
interleaves rows of two or more tables in the same storage area.
What is a table scan - CORRECT ANSWER A database operation that
reads table blocks directly without using an index.
What is an index scan - CORRECT ANSWER A database operation
that reads index blocks sequentially to locate the needed table blocks.
What is a hit ratio (filter factor - CORRECT ANSWER selectivity), The
percentage of table rows selected by a query.
What is a binary search - CORRECT ANSWER A search method
where the database repeatedly splits the index in two until the search
value is found.
What is a dense index - CORRECT ANSWER An index that contains
an entry for every table row.
What is a sparse index - CORRECT ANSWER An index that contains
an entry for every table block.
What is a hash index - CORRECT ANSWER An index where entries
are assigned to buckets.
ACTUAL EXAM 300 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
What is a subquery - CORRECT ANSWER A query within another SQL
query.
What is an alias in SQL - CORRECT ANSWER A temporary name
assigned to a column or table, created with the AS keyword.
What is a materialized view - CORRECT 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 - CORRECT ANSWER
Ensures that inserts and updates in a view satisfy the view's WHERE
clause.
What is an entity in entity-relationship modeling - CORRECT ANSWER
A person, place, product, concept, or activity.
What is a relationship in entity-relationship modeling - CORRECT
ANSWER A statement about two entities.
What is an attribute in entity-relationship modeling - CORRECT
ANSWER A descriptive property of an entity.
What is a reflexive relationship - CORRECT ANSWER A relationship
that relates an entity to itself.
What is an entity-relationship diagram (ER diagram) - CORRECT
ANSWER A schematic picture of entities, relationships, and
attributes, where entities are drawn as rectangles.
What is an entity type - CORRECT ANSWER A set of things, such as
all employees in a company.
,What is a relationship type - CORRECT ANSWER A set of related
things, such as employee-manages-department pairs.
What is an attribute type - CORRECT ANSWER A set of values, such
as all employee salaries.
What is an entity instance - CORRECT ANSWER An individual thing,
such as the employee Sam Snead.
What is a relationship instance - CORRECT ANSWER A specific
statement about entity instances, such as "Maria Rodriguez manages
Sales."
What is an attribute instance - CORRECT ANSWER An individual
value, such as a salary of $35,000.
What is cardinality in entity-relationship modeling - CORRECT
ANSWER The maxima and minima of relationships and attributes.
What is a subtype entity - CORRECT ANSWER A subset of another
entity type, called the supertype entity.
What is a supertype entity - CORRECT ANSWER An entity that has
one or more subtype entities, such as "vehicle" with subtypes like
"car" and "truck."
What is an IsA relationship - CORRECT ANSWER The identifying
relationship between a supertype and its subtypes.
What is a partition in entity-relationship modeling - CORRECT ANSWER
A group of mutually exclusive subtype entities within a supertype
entity.
What is crow's foot notation - CORRECT 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 - CORRECT ANSWER An entity
documented in the data model but not tracked with data in the
database.
What are the characteristics of a primary key - CORRECT ANSWER A
primary key should be stable, simple, and meaningless.
What is an artificial key - CORRECT ANSWER A single-column
primary key created by the database designer when no suitable
primary key exists.
What is functional dependence - CORRECT ANSWER The
dependence of one column on another.
What is redundancy in databases - CORRECT ANSWER The
repetition of related values in a table.
What is a candidate key - CORRECT ANSWER A simple or composite
column that is unique and minimal, with all columns necessary for
uniqueness.
What is a non-key column - CORRECT ANSWER A column that is not
contained in a candidate key.
What is third normal form - CORRECT 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 - CORRECT 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 - CORRECT ANSWER When the columns
of A are a subset of the columns of B, A always depends on B.
What is normalization - CORRECT ANSWER The process of
eliminating redundancy by decomposing a table into two or more
tables in higher normal form.
, What is denormalization - CORRECT ANSWER The intentional
introduction of redundancy by merging tables.
What is a heap table - CORRECT ANSWER A table where no order is
imposed on rows, optimizing insert operations.
What is a sorted table - CORRECT ANSWER A table where rows are
physically ordered by a specified sort column.
What is a hash table - CORRECT ANSWER A table where rows are
assigned to buckets, optimizing search and retrieval.
What is a table cluster - CORRECT ANSWER A storage structure that
interleaves rows of two or more tables in the same storage area.
What is a table scan - CORRECT ANSWER A database operation that
reads table blocks directly without using an index.
What is an index scan - CORRECT ANSWER A database operation
that reads index blocks sequentially to locate the needed table blocks.
What is a hit ratio (filter factor - CORRECT ANSWER selectivity), The
percentage of table rows selected by a query.
What is a binary search - CORRECT ANSWER A search method
where the database repeatedly splits the index in two until the search
value is found.
What is a dense index - CORRECT ANSWER An index that contains
an entry for every table row.
What is a sparse index - CORRECT ANSWER An index that contains
an entry for every table block.
What is a hash index - CORRECT ANSWER An index where entries
are assigned to buckets.
