title: Renaming hstore key in PostgreSQL 9.2
body: <p>I've been evaluating PostgreSQL's hstore functionality (9.2) and the only thing the <a href="http://www.postgresql.org/docs/current/static/hstore.html" rel="noreferrer">fine manual</a> isn't explicit about is how to rename keys. For instance, how could I rename the  key <code>c</code> to <code>ai_count</code>?</p>
  
  <p><code>"c"=&gt;"3", "ai_voltage"=&gt;"3", "ai_temperature"=&gt;"28"</code></p>
  
  <p>I'm thinking there is no direct way to do this and that it involves duplicating the <code>c</code> key to a <code>ai_count</code> key, then dropping the <code>c</code> key. How can I do this, ideally as a one-liner which can be applied to multiple records?</p>