Exam 70-464 topic 1 question 90 discussion

You have a Microsoft Azure SQL Database instance.
The database contains a disk-based table named ContentTable that has 1 million rows and a column named Fax. Fax allows null values.
You need to update Fax to meet the following requirements:
✑ Prevent null values from being used.
✑ Always use an empty string instead of a null value.
Which statement or statements should you execute? (Each correct answer presents part of the solution. Choose all that apply.)