title: Column is not the same data type as referencing column
body: <p>I'm altering table to add a foreign key as following:</p>
  
  <pre><code>ALTER TABLE [MS_Test].[dbo].[Studies]
     ADD CONSTRAINT F_Id
         FOREIGN KEY (Id) REFERENCES [M_Test].[dbo].[MS](Id);
  </code></pre>
  
  <p>I get the following error: </p>
  
  <blockquote>
    <p>Msg 1778, Level 16, State 0, Line 2<br>
    Column 'MS_Test.dbo.FM.Id' is not the same data type as referencing column 'Studies.Id' in foreign key 'F_Id'.</p>
    
    <p>Msg 1750, Level 16, State 0, Line 2<br>
    Could not create constraint or index. See previous errors.</p>
  </blockquote>
  
  <p>I have already a lot of data stored in my tables so I can't just drop table and create it again. </p>