title: Codeigniter: Active Records Insert Unique values
body: <p>I am importing GMail contacts from Google API and just want to persist unique email ids into database.
  Is it possible to insert unique records using codeigniter's Active Record? 
  Does CodeIgniter provide it out of the box?<br/>
  If I make the column unique the query throws exception. After digging into documentation I understood that CodeIgniter doesn't provide <code>try catch</code> blocks.</p>