Converting nvarchar to varchar

Question

I have a database with a lot of varchar columns. My datalayer, which is entity framework, interfaces with it.

If I were to change all the column types from varchar to nvarchar, would it be safe?

Would I have to change any of my C# code from data layer all the way to presentation?

Answer 1

No, NVARCHAR takes up twice as much space as VARCHAR, so going the other way might cause you to lose data, but going this direction should be fine.