title: Store entities with varying attributes (EAV alternative)
body: <p>I'm looking for a way to store EAV-like subject on a relational DB. I'm going to use Rails + Mysql. I had little expirience with EAV in PHP + Mysql. ~500 entries. That's nothing, of course, all queries was fast (though there was no query caching). But what if a million records? What to do? Use MongoDB? Or maybe Sphinx can help in this situation? Or maybe SQL+NoSQL tandeme?</p>
  
  <p>In short, what is the best way?
  P.S. I'm complete noob in Rails yet, switching with PHP, so tell me, what could be the pitfalls.</p>
  
  <p>Sorry for my english)</p>