title: MongoDB multiple schemas in one collection
body: <p>I am new to mongo and have done a lot of reading and a proof of concept. There are many discussions about multiple collections or embedded documents. Isn't there another choice? Ignoring my relationalDB mind... Couldn't you put two different schemas in the same collection?</p>
  
  <p>Crude example:</p>
  
  <pre><code>{
      _id: 'f48a2dea-e6ec-490d-862a-bd1791e76d9e',
      _owner: '7a147aad-e3fd-4e55-9fd5-e2cb48d31a83'
      manufacturer: 'Porsche',
      model: '911',
      img: '&lt;byte array&gt;'
  },{
      _id: '821ca9b7-faa1-4516-a27e-aec79fcb89a9',
      _owner: '46ade116-cd59-4d0c-a4d3-cd2e517a256c',
      manufacturer: 'Nissan',
      model: 'GT-R',
      img: '&lt;byte array&gt;'
  },{
      _id: '87999e27-c98b-4cad-b444-75626f161840'
      _owner: 'fba765c8-32dd-49ba-91d3-d361b40bf4a7',
      manufacturer: 'BMW',
      model: 'M3',
      wiki:'http://en.wikipedia.org/wiki/Bmw_m3',
      img: '&lt;byte array&gt;'
  }
  </code></pre>
  
  <p>and a totally difference schema in the same collection as well</p>
  
  <pre><code>{
      _id: '7a147aad-e3fd-4e55-9fd5-e2cb48d31a83',
      name: 'Keeley Bosco',
      email: 'katlyn@jenkinsmaggio.net,
      city": 'Lake Gladysberg',
      mac: '08:fd:0b:cd:77:f7',
      timestamp: '2015-04-25 13:57:36 +0700',
  },{
      _id: '46ade116-cd59-4d0c-a4d3-cd2e517a256c',
      name: 'Rubye Jerde',
      email: 'juvenal@johnston.name',
      city: null,
      mac: '90:4d:fa:42:63:a2',
      timestamp: '2015-04-25 09:02:04 +0700',
  },{
      _id: 'fba765c8-32dd-49ba-91d3-d361b40bf4a7',
      name: 'Miss Darian Breitenberg',
      email: null,
      city: null,
      mac: 'f9:0e:d3:40:cb:e9',
      timestamp: '2015-04-25 13:16:03 +0700',
   }
  </code></pre>
  
  <p>(The reason I don't use an embedded document (in my real POC) is that a person may have 80000 "cars" and go over the 16MB limit).</p>
  
  <p>Besides the aching desire to compartmentalize data is there a downfall here?</p>
  
  <p>The reasoning for doing this <em>may</em> be so that we can correlate the records... I do see that 3.2 has join. The project it too new to know all of the business cases.</p>