title: "You cannot add or change a record because a related record is required", but related record exists?
body: <p>I have two related tables, <code>results</code> and <code>userID</code>.</p>
  
  <p><code>results</code> looks like this:</p>
  
  <pre><code>+----+--------+--------+
  | ID | userID | result |
  +----+--------+--------+
  |  1 | abc    |    124 |
  |  2 | abc    |    792 |
  |  3 | def    |    534 |
  +----+--------+--------+
  </code></pre>
  
  <p><code>userID</code> looks like this:</p>
  
  <pre><code>+----+--------+---------+
  | id | userID |  name   |
  +----+--------+---------+
  |  1 | abc    | Angela  |
  |  2 | def    | Gerard  |
  |  3 | zxy    | Enrico  |
  +----+--------+---------+
  </code></pre>
  
  <p>In <code>results</code>, the <code>userID</code> field is a lookup field; it stores <code>userID.id</code> but the combo box has <code>userID.userID</code> as its choices.</p>
  
  <p>When I try to enter data into <code>results</code> by setting the <code>userID</code> combo box and entering a value for result, I get this error message:</p>
  
  <pre><code>You cannot add or change a record because a related record
  is required in table `userID`.
  </code></pre>
  
  <p>This is strange, because I'm specifically selecting a value that's provided in the <code>userID</code> combo box.</p>
  
  <p>Oddly, there are about 100 rows of data already in <code>results</code> with the same value for <code>userID</code>.</p>
  
  <p>I thought this might be a database corruption issue, so i created a blank database and imported all the tables into it.  But I still got the same error.  What's going on here?</p>