WGU D427 Practice Test 1 with ANSWER KEY

D427 Practice Test 1
1. Seattle, WA 98111
USA
How many attributes are present in the address fragment?

a. 1
b. 2
c. 3
d. 4

2. The Book table has the following columns:
genre – varchar(20)
pages – integer
author_id – char(3)
isbn_number – varchar(20)
Which column should be designated as the primary key for the Book table?

a. genre
b. pages
c. author_id
d. isbn_number

3. The Book table has the following columns:
genre – varchar(20)
pages – integer
author_id – char(3)
isbn_number – varchar(20)
Which column should be designated as the foreign key for the Book table?

a. genre
b. pages
c. author_id
d. isbn_number

4. Which data type represents numbers with fractional values:

a. Integer
b. Decimal
c. Character
d. Binary

,5. Which of the following is a DDL commands?

a. INSERT
b. SELECT
c. CREATE INDEX
d. UPDATE


6. Which of the following is a DML command?

a. CREATE VIEW
b. CREATE TABLE
c. INSERT
d. ALTER INDEX


7.
CREATE TABLE Invoice (
invoice_id INT NOT NULL AUTO_INCREMENT,
date DATE NOT NULL,
customer_id INT NOT NULL UNIQUE,
PRIMARY KEY (invoice_id),
FOREIGN KEY (customer_id) REFERENCES Customer (customer_id) ON DELETE
CASCADE
);
Looking at the Customer and Invoice tables and the CREATE TABLE for the Invoice table with
foreign key reference statement above, what would happen to invoices in the Invoice table that are
linked to a customer if that customer is deleted.


a. Those invoices would remain in the database.
b. Those invoices would be deleted also.
c. The Customer ID for those invoices would be changed to NULL.
d. Nothing would happen.


Customer ID (PK) Invoice ID (PK)
Customer Last Name Date
Customer First Name Customer ID (FK)
Street Address
City
State
Zip

, 8. CREATE TABLE Invoice (
invoice_id INT NOT NULL AUTO_INCREMENT,
date DATE NOT NULL,
customer_id INT NOT NULL,
PRIMARY KEY (invoice_id),
FOREIGN KEY (customer_id) REFERENCES Customer (customer_id) ON DELETE
RESTRICT
);


Looking at the Customer and Invoice tables and the CREATE TABLE for the Invoice table with
foreign key reference statement above, what would happen to invoices in the Invoice table that are
linked to a customer if that customer is deleted.


a) Those customers would remain in the customer database.
b) Those invoices would be deleted also.
c) The Customer ID for those invoices would be changed to NULL.
d) The delete of the invoices would not be allowed.


Customer ID (PK) Invoice ID (PK)
Customer Last Name Date
Customer First Name Customer ID (FK)
Street Address
City
State
Zip


9. CREATE TABLE Invoice (
invoice_id INT NOT NULL AUTO_INCREMENT,
date DATE NOT NULL,
customer_id INT NOT NULL,
PRIMARY KEY (invoice_id),
FOREIGN KEY (customer_id) REFERENCES Customer (customer_id) ON DELETE SET TO
NULL
);