title: The columns in 'table_XXX' do not match an existing primiary key or UNIQUE constraint
body: <p>I have 2 simple tables designed as shown below:</p>
  
  <p>Users:</p>
  
  <p><img src="https://i.stack.imgur.com/svqs4.png" alt="enter image description here"></p>
  
  <p>Categories:</p>
  
  <p><img src="https://i.stack.imgur.com/gdUT7.png" alt="enter image description here"></p>
  
  <p>Now I would like to set the username as foreign key on categories table so this is what I have done but getting the error as shown below:</p>
  
  <p><img src="https://i.stack.imgur.com/3QvA7.png" alt="enter image description here"></p>
  
  <p>Am I doing the right way? Or can anyone suggest me the right way of doing this ?</p>
  
  <p><strong>*NOTE:</strong> I have tried to remove the primary key from the 2 tables and added them back and tried but showing me the same error.</p>