WGU D426 Questions with Detailed Verified
Answers
A ____ is a column, or group of columns, used to identify a row. Ans: Primary key
A ____ consists of a single column. Ans: Simple primary key
A ____ key consists of multiple columns. Ans: 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. Ans: 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. Ans: Primary key
An _____ is a numeric column that is assigned an automatically incrementing value
when a new row is inserted. Ans: Auto-increment column
The ____ keyword defines an auto-increment column. It follows the column's data
type in a CREATE TABLE statement. Ans: AUTO_INCREMENT
A ____ is a column, or group of columns, that refer to a primary key. Ans: Foreign
key
____ requires foreign key values must either be NULL or match some value of the
referenced primary key. Ans: Referential integrity
A ____ constraint is added to a CREATE TABLE statement with the ____ and
REFERENCES keywords. Ans: Foreign key; references
A ____ foreign key is a simple or composite foreign key in which all columns are
NULL. Ans: Fully NULL
____ is a relational rule that requires foreign key values to either be fully NULL or
match some primary key value. Ans: Referential integrity
, ____ rejects an insert, update, or delete that violates referential integrity. Ans:
RESTRICT
____ sets invalid foreign keys to NULL. Ans: SET NULL
____ sets invalid foreign keys to the foreign key default value. Ans: SET DEFAULT
____ propagates primary key changes to foreign keys. Ans: 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. Ans: 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. Ans: Constraint(s)
A ____ appears after the column name and data type in a CREATE TABLE statement.
Column constraints govern values in a single column. Ans: Column constraint
A ____ appears in a separate clause of a CREATE TABLE statement and governs
values in one or more columns. Ans: Table constraint
The ____ constraint ensures that values in a column, or group of columns, are unique.
Ans: 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. Ans: CHECK
Table ____ may be names using the optional CONSTRAINT keyword, followed by the
constraint name and declaration. Ans: CONSTRAINT
An ____ is a high-level representation of data requirements, ignoring implementing
details. Ans: Entity-relationship model
© Get it right 2025 Getaway - Stuvia US All rights reserved
Answers
A ____ is a column, or group of columns, used to identify a row. Ans: Primary key
A ____ consists of a single column. Ans: Simple primary key
A ____ key consists of multiple columns. Ans: 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. Ans: 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. Ans: Primary key
An _____ is a numeric column that is assigned an automatically incrementing value
when a new row is inserted. Ans: Auto-increment column
The ____ keyword defines an auto-increment column. It follows the column's data
type in a CREATE TABLE statement. Ans: AUTO_INCREMENT
A ____ is a column, or group of columns, that refer to a primary key. Ans: Foreign
key
____ requires foreign key values must either be NULL or match some value of the
referenced primary key. Ans: Referential integrity
A ____ constraint is added to a CREATE TABLE statement with the ____ and
REFERENCES keywords. Ans: Foreign key; references
A ____ foreign key is a simple or composite foreign key in which all columns are
NULL. Ans: Fully NULL
____ is a relational rule that requires foreign key values to either be fully NULL or
match some primary key value. Ans: Referential integrity
, ____ rejects an insert, update, or delete that violates referential integrity. Ans:
RESTRICT
____ sets invalid foreign keys to NULL. Ans: SET NULL
____ sets invalid foreign keys to the foreign key default value. Ans: SET DEFAULT
____ propagates primary key changes to foreign keys. Ans: 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. Ans: 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. Ans: Constraint(s)
A ____ appears after the column name and data type in a CREATE TABLE statement.
Column constraints govern values in a single column. Ans: Column constraint
A ____ appears in a separate clause of a CREATE TABLE statement and governs
values in one or more columns. Ans: Table constraint
The ____ constraint ensures that values in a column, or group of columns, are unique.
Ans: 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. Ans: CHECK
Table ____ may be names using the optional CONSTRAINT keyword, followed by the
constraint name and declaration. Ans: CONSTRAINT
An ____ is a high-level representation of data requirements, ignoring implementing
details. Ans: Entity-relationship model
© Get it right 2025 Getaway - Stuvia US All rights reserved
