title: Arangodb insert multiple rows and using UPSERT
body: <p>how do i insert multiple rows in arangodb with UPSERT?
  Collection contains a unique index which prevent insert duplicate documents.
  multiple insert work fine without unique index, but how can i handle update/replace  in multiple insert with unique index?</p>
  
  <p>like this:</p>
  
  <pre><code>INSERT [{doc1},{doc2},{doc3}]
  IN collection
  
  UPDATE {} // when duplicate per document
  </code></pre>
  
  <hr>
  
  <p><strong>Update 1</strong></p>
  
  <p>SQL look like this:</p>
  
  <pre><code>INSERT INTO table(name, value)
  VALUES('a', '1'), ('b', 2), ('c', 3)
  
  ON DUPLICATE KEY UPDATE name=`value`
  </code></pre>
  
  <p>thanks.</p>