do you have to specify the length of the type in a sproc parameter?

Question

Does SQL Server allow you to declare stored procedure parameters like this?

@username NVARCHAR

Or do you always have to specify a size like this?

@username NVARCHAR(100)

Answer 1

If you don't specify a length it will default to 1. Even if that is your intention it is better to be explicit like this:

nvarchar(1)

Edit: I should have pointed out that my previous statement only applies to declarations - if you are using nvarchar in a cast statement and omit a length it will default to 30.

Answer 2

You do not need to specify a length, at least in SQL Server 2005, but it is a good practice to do so.