title: Big Query Streaming API to overwrite rows using insertId
body: <p>When using the Big Query streaming api, and setting an <code>insertId</code> on each row, we can update (overwrite) rows by performing subsequent inserts with the same <code>insertId</code>.</p>
  
  <p>This behaviour is not mentioned in the <a href="https://cloud.google.com/bigquery/streaming-data-into-bigquery#dataconsistency" rel="nofollow">documentation</a>, as only states:</p>
  
  <blockquote>
    <p>BigQuery uses the insertId property to de-duplicate your data on a best effort basis.</p>
  </blockquote>
  
  <p>Will Big Query always overwrite rows with the same insertId?</p>
  
  <p>Could this be potential be used to update data?</p>