title: Alter NVARCHAR column from NULL to NOT NULL in sql server
body: <p>I've created a table column called RateValue with initially allowing NULL value but I want to make it NOT NULL. I used <strong>SQL Server 2008 R2</strong></p>
  
  <p>I tried the following but it does not work</p>
  
  <pre><code>ALTER TABLE dbo.AAElement
  ALTER COLUMN RateValue NVARCHAR(50) NOT NULL
  </code></pre>