MySQL Lesson 10 Review

A (a)   is used to allow or restrict what values will be stored in the column

A (a)   key constraint is used to prevent duplicate values

A (a)   key constraint does not allow NULL values

A primary key constraint is used to make an entire row (a)  

A primary key constraint can only be added when creating a table

• True

• False

A primary key constraint can be dropped only when the column is dropped first

• True

• False

Condition: The table has already been made but no primary key constraint has been added. Now you want to add it and the column already contains duplicate values. What will happen when you execute the code?

• It will run without a problem.

• It will not run.

There should only be ___ (number) primary key for each table.

• 1

• 2

• 3

• 4

There can be multiple (a)   keys in a table.

You are trying to add a value "103" to a column and it outputs Duplicate entry "103". How could you solve this issue? Choose all the correct ways.

• Remove the row with the original 103 value from the column

• Change the original 103 in the column to another value

• Change the 103 value that you want to input to another value

• Remove the primary key constraint