title: ElasticSearch Wrapping Head on Index Types
body: <p>I'm looking into elastic search right now and I am having a hard time grasping how index types fit into the data model, I've read examples and documentation but none really goes in depth or the examples seem to use a data model that is composed of several submodels.</p>
  
  <p>I am currently using mongodb to store my data, let's take this example of an Article collection that I want to be indexed for search, my doc looks like this:</p>
  
  <pre><code>Article = {
      title: String,
      publisher: String,
      subject: String,
      description: String,
      year: Integer,
  }
  </code></pre>
  
  <p>Now I want each of those fields to be searchable, so I would make an elasticsearch index of 'Article'. I will need to define each field and how it should be analysed and whether it is stored or not, that I understand.</p>
  
  <p>Now how does an index type come in here? As far as I am aware, Lucene does not have this concept, this is a layer added by Elasticsearch.</p>
  
  <p>For example, maybe some of you may say that we can logically group the documents by subject  or publisher and create index types on those but how is this different from searching by subject or publisher? </p>
  
  <p>Is it more of a performance related aspect that we have index types?</p>