title: SQL rules being ignored
body: <p>I have two tables on a SQL database:</p>
  
  <p><code>MODEL</code> (<code>ID_MODEL</code>, <code>MODEL</code>, <code>ID_manu</code>, <code>ID_CLASS</code>) and <code>CLASS</code> ( <code>ID_CLASS</code>, <code>CLASS</code>)</p>
  
  <p>They are linked using the <code>ID_CLASS</code>.</p>
  
  <p>The query to delete information has a none rule, so it's supposed to give an error when I try to delete a row from <code>CLASS</code>, if the <code>ID_CLASS</code> is being used on the <code>MODEL</code> table.</p>
  
  <p>But it's being ignored. It's deleting the <code>CLASS</code> from the <code>CLASS</code> table and the row on the <code>MODEL</code> table is removed from the <code>DataGridView</code>, but it's kept on the table.</p>
  
  <p>The <code>ID_CLASS</code> options on <code>MODEL</code>is a <code>NOT NULL</code> as you can see below:</p>
  
  <pre><code>CREATE TABLE [dbo].[MODEL] (
      [ID_MODEL] INT          IDENTITY (1, 1) NOT NULL,
      [MODEL]    VARCHAR (50) NOT NULL,
      [ID_manu]  INT          NOT NULL,
      [ID_CLASS] INT          NOT NULL,
      PRIMARY KEY CLUSTERED ([ID_MODEL] ASC),
      UNIQUE NONCLUSTERED ([MODEL] ASC)
  );
  </code></pre>
  
  <p>Even after deleting and recreating the relationship its still happening.</p>
  
  <p>Also there are two other tables with a similar configuration (same rule and data type) and on that it's working as expected. It retrieves an error every time the delete query is run.</p>