title: SQL SERVER Check constraint - Querying other rows
body: <p>I want to enforce a business rule on my database table to ensure that a row can't be inserted if the table already contains rows meeting a certain criteria.</p>
  
  <p>Was wanting to use a CHECK constraint but suspect this may have to be done via a trigger.</p>
  
  <p>Is there a way to do this via a CHECK constraint? OR is there another way to do this at the database level without using a trigger?</p>