title: indexing different record types in one single solr schema
body: <p>I am struggling with the overall view of how (whether possible) one might be able to index multiple different types of records in one single Solr core. <em>Multiple records meaning that they have different unique keys</em>. </p>
  
  <p>We are inclined to want to use a single core because we want to be able to, at certain levels, search everything all at once and not have to cobble cores together.</p>
  
  <p>So, for example, I have <strong>products</strong> that have the fields:</p>
  
  <pre><code>product_code &lt;--- unique key
  product_title 
  product_description 
  etc...
  </code></pre>
  
  <p>then there are <strong>job listings</strong> that have the fields: <br/></p>
  
  <pre><code>job_id &lt;---- unique key
  job_description
  job_title
  etc... 
  </code></pre>
  
  <p>there are multiple other entities, including a <a href="http://nutch.apache.org/" rel="nofollow">Nutch</a> search index, which will have a unique id of 'id'</p>
  
  <p>is it possible to include in the schema.xml more than one unique key? so that id do not have to send each different kind of record to a different solr core?</p>
  
  <p>The main concern I have is that in identifying the <code>&lt;uniqueKey&gt;</code>s at least one of them has to be required, but not all records sent to the solr index will have the required key.</p>
  
  <p>Is there an accepted way to get around this problem in Solr?</p>