Section 11.1 Oracle Quiz

Section 1
(Answer all questions in this section)

1. Identify all of the correct statements that complete this sentence: A primary key is: (Choose Three) (Choose all correct answers)

• A single column that uniquely identifies each row in a table (*)
• A set of columns that uniquely identifies each row in a table (*)
• A set of columns and keys in a single table that uniquely identifies each row in a single table (*)
• Only one column that cannot be null

2. A table does not have to have a primary key. True or False?

• True (*)
• False

3. One or more columns in a primary key can be null. True or False? 

• True
• False (*)

4. A foreign key always refers to a primary key in the same table. True or False?

• True
• False (*)

5. Foreign keys cannot be null when

• It is part of a primary key (*)
• It refers to another table
• It contains three or more columns

6. Column integrity refers to

• Columns always having values
• Columns always containing positive numbers
• Columns always containing values consistent with the defined data format (*)
• Columns always containing text data less than 255 characters

7. The explanation below is an example of which constraint type?
A primary key must be unique, and no part of the primary key can be null.

• Entity integrity (*)
• Referential integrity
• Column integrity
• User-defined integrity

8. The explanation below is an example of which constraint type?
A column must contain only values consistent with the defined data format of the column

• Entity integrity
• Referential integrity
• Column integrity (*)
• User-defined integrity

9. The explanation below is an example of which constraint type?
The value in the dept_no column of the EMPLOYEES table must match a value in the dept_no column in the DEPARTMENTS table.

• Entity integrity
• Referential integrity (*)
• Column integrity
• User-defined integrity

10. The explanation below is an example of which constraint type?
If the value in the balance column of the ACCOUNTS table is below 100, we must send a letter to the account owner which will require extra programming to enforce.

• Entity integrity
• Referential integrity
• Column integrity
• User-defined integrity (*)