title: Foreign key constraint may cause cycles or multiple cascade paths?
body: <p>I have a problem when I try to add constraints to my tables. I get the error:</p>
  
  <blockquote>
    <p>Introducing FOREIGN KEY constraint 'FK74988DB24B3C886' on table 'Employee' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.</p>
  </blockquote>
  
  <p>My constraint is between a <code>Code</code> table and an <code>employee</code> table. The <code>Code</code> table contains <code>Id</code>, <code>Name</code>, <code>FriendlyName</code>, <code>Type</code> and a <code>Value</code>. The <code>employee</code> has a number of fields that reference codes, so that there can be a reference for each type of code.</p>
  
  <p>I need for the fields to be set to null if the code that is referenced is deleted.</p>
  
  <p>Any ideas how I can do this?</p>