title: How to continue a sequence when inserting
body: <p>I have tried to simplify my question with the following example:</p>
  
  <p>I have a table with the following data:</p>
  
  <pre><code>Marker     Name            Location
  1          Eric Benson     Mixed
  2          John Smith      Rural
  3          A David         Rural
  4          B John          Mixed
  </code></pre>
  
  <p>And i want to insert into the table:</p>
  
  <pre><code>Name            Location
  Andy Jones      Mixed
  Ian Davies      Rural
  </code></pre>
  
  <p>How can i continue the sequencein the Marker column to end up with:</p>
  
  <pre><code>Marker     Name            Location
  1          Eric Benson     Mixed
  2          John Smith      Rural
  3          A David         Rural
  4          B John          Mixed
  5          Andy Jones      Mixed
  6          Ian Davies      Rural
  </code></pre>