D426 WGU EXAM AND PRACTICE EXAM NEWEST
ACTUAL EXAM COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+
A ____ is a column, or group of columns, used to identify a row. -
CORRECT ANSWER Primary key
A ____ consists of a single column. - CORRECT ANSWER Simple
primary key
A ____ key consists of multiple columns. - CORRECT ANSWER
Composite primary
All primary keys columns are necessary for uniqueness. When any
column is removed, the resulting simple or composite column is no
longer unique. - CORRECT ANSWER Minimal
The ____ constraint in the CREATE TABLE statement names the table's
____. The ____ constraint ensures that a column or group of columns is
always unique and non-null. - CORRECT ANSWER Primary key
An _____ is a numeric column that is assigned an automatically
incrementing value when a new row is inserted. - CORRECT ANSWER
Auto-increment column
The ____ keyword defines an auto-increment column. It follows the
column's data type in a CREATE TABLE statement. - CORRECT
ANSWER AUTO_INCREMENT
A ____ is a column, or group of columns, that refer to a primary key. -
CORRECT ANSWER Foreign key
,____ requires foreign key values must either be NULL or match some
value of the referenced primary key. - CORRECT ANSWER Referential
integrity
A ____ constraint is added to a CREATE TABLE statement with the ____
and REFERENCES keywords. - CORRECT ANSWER Foreign key;
references
A ____ foreign key is a simple or composite foreign key in which all
columns are NULL. - CORRECT ANSWER Fully NULL
____ is a relational rule that requires foreign key values to either be
fully NULL or match some primary key value. - CORRECT ANSWER
Referential integrity
____ rejects an insert, update, or delete that violates referential
integrity. - CORRECT ANSWER RESTRICT
____ sets invalid foreign keys to NULL. - CORRECT ANSWER SET
NULL
____ sets invalid foreign keys to the foreign key default value. -
CORRECT ANSWER SET DEFAULT
____ propagates primary key changes to foreign keys. - CORRECT
ANSWER CASCADE
Actions are specified in the optional ____ and ____ clauses of the
FOREIGN KEY constraint. ____ and ____ are followed by either
RESTRICT, SET NULL, SET DEFAULT, or CASCADE. - CORRECT
ANSWER ON UPDATE and ON DELETE
A ____ is a rule that governs allowable values in a database. ____ are
based on relational and business rules, and implemented with special
keywords in a CREATE TABLE statement. The database automatically
rejects insert, update, and delete statements that violate a constraint.
- CORRECT ANSWER Constraint(s)
, A ____ appears after the column name and data type in a CREATE
TABLE statement. Column constraints govern values in a single
column. - CORRECT ANSWER Column constraint
A ____ appears in a separate clause of a CREATE TABLE statement and
governs values in one or more columns. - CORRECT ANSWER Table
constraint
The ____ constraint ensures that values in a column, or group of
columns, are unique. - CORRECT ANSWER UNIQUE
The ____ constraint specifies an expression on one or more columns of
a table. The constraint is violated when the expression is FALSE and
satisfied when the expression is either TRUE or NULL. - CORRECT
ANSWER CHECK
Table ____ may be names using the optional CONSTRAINT keyword,
followed by the constraint name and declaration. - CORRECT ANSWER
CONSTRAINT
An ____ is a high-level representation of data requirements, ignoring
implementing details. - CORRECT ANSWER Entity-relationship model
An ____ is a person, place, product, concept, or activity. - CORRECT
ANSWER Entity
A ____ is a statement about two entities. - CORRECT ANSWER
Relationship
An ____ is a descriptive property of an entity. - CORRECT ANSWER
Attribute
A ____ relates an entity to itself. - CORRECT ANSWER Reflexive
relationship
An ____, commonly called an ER diagram, is a schematic picture of
entities, relationships, and attributes. - CORRECT ANSWER Entity-
relationship diagram (ER diagram)
ACTUAL EXAM COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+
A ____ is a column, or group of columns, used to identify a row. -
CORRECT ANSWER Primary key
A ____ consists of a single column. - CORRECT ANSWER Simple
primary key
A ____ key consists of multiple columns. - CORRECT ANSWER
Composite primary
All primary keys columns are necessary for uniqueness. When any
column is removed, the resulting simple or composite column is no
longer unique. - CORRECT ANSWER Minimal
The ____ constraint in the CREATE TABLE statement names the table's
____. The ____ constraint ensures that a column or group of columns is
always unique and non-null. - CORRECT ANSWER Primary key
An _____ is a numeric column that is assigned an automatically
incrementing value when a new row is inserted. - CORRECT ANSWER
Auto-increment column
The ____ keyword defines an auto-increment column. It follows the
column's data type in a CREATE TABLE statement. - CORRECT
ANSWER AUTO_INCREMENT
A ____ is a column, or group of columns, that refer to a primary key. -
CORRECT ANSWER Foreign key
,____ requires foreign key values must either be NULL or match some
value of the referenced primary key. - CORRECT ANSWER Referential
integrity
A ____ constraint is added to a CREATE TABLE statement with the ____
and REFERENCES keywords. - CORRECT ANSWER Foreign key;
references
A ____ foreign key is a simple or composite foreign key in which all
columns are NULL. - CORRECT ANSWER Fully NULL
____ is a relational rule that requires foreign key values to either be
fully NULL or match some primary key value. - CORRECT ANSWER
Referential integrity
____ rejects an insert, update, or delete that violates referential
integrity. - CORRECT ANSWER RESTRICT
____ sets invalid foreign keys to NULL. - CORRECT ANSWER SET
NULL
____ sets invalid foreign keys to the foreign key default value. -
CORRECT ANSWER SET DEFAULT
____ propagates primary key changes to foreign keys. - CORRECT
ANSWER CASCADE
Actions are specified in the optional ____ and ____ clauses of the
FOREIGN KEY constraint. ____ and ____ are followed by either
RESTRICT, SET NULL, SET DEFAULT, or CASCADE. - CORRECT
ANSWER ON UPDATE and ON DELETE
A ____ is a rule that governs allowable values in a database. ____ are
based on relational and business rules, and implemented with special
keywords in a CREATE TABLE statement. The database automatically
rejects insert, update, and delete statements that violate a constraint.
- CORRECT ANSWER Constraint(s)
, A ____ appears after the column name and data type in a CREATE
TABLE statement. Column constraints govern values in a single
column. - CORRECT ANSWER Column constraint
A ____ appears in a separate clause of a CREATE TABLE statement and
governs values in one or more columns. - CORRECT ANSWER Table
constraint
The ____ constraint ensures that values in a column, or group of
columns, are unique. - CORRECT ANSWER UNIQUE
The ____ constraint specifies an expression on one or more columns of
a table. The constraint is violated when the expression is FALSE and
satisfied when the expression is either TRUE or NULL. - CORRECT
ANSWER CHECK
Table ____ may be names using the optional CONSTRAINT keyword,
followed by the constraint name and declaration. - CORRECT ANSWER
CONSTRAINT
An ____ is a high-level representation of data requirements, ignoring
implementing details. - CORRECT ANSWER Entity-relationship model
An ____ is a person, place, product, concept, or activity. - CORRECT
ANSWER Entity
A ____ is a statement about two entities. - CORRECT ANSWER
Relationship
An ____ is a descriptive property of an entity. - CORRECT ANSWER
Attribute
A ____ relates an entity to itself. - CORRECT ANSWER Reflexive
relationship
An ____, commonly called an ER diagram, is a schematic picture of
entities, relationships, and attributes. - CORRECT ANSWER Entity-
relationship diagram (ER diagram)
