title: How to modify an unique row from duplicated rows
body: <p>I am working with an existing Pervasive <strong>v10</strong> database. In a table I have duplicated rows without an unique descriptor (no primary key).</p>
  
  <p>I would like to modify only the first row with the SQL command update. The table History have 3 columns only : </p>
  
  <ul>
  <li>Document : a VARCHAR</li>
  <li>Link : a number</li>
  <li>Description : a VARCHAR</li>
  </ul>
  
  <p>The result of :</p>
  
  <pre><code>select * from History where Document = 'IN10001' and Link = 3
  </code></pre>
  
  <p>is giving 2 identical rows :</p>
  
  <blockquote>
    <p>'IN10001'; 3; 'Invoice 2' </p>
    
    <p>'IN10001'; 3; 'Invoice 2'</p>
  </blockquote>
  
  <p>Could someone help me to change the field: Link for only one row?</p>