title: MongoDB query: how to check if a string stored in a document is contained in another string
body: <p>I have a collection with 8k+ strings and I need to check if a particular string is contained in another string. For example:</p>
  
  <pre><code>StringInDb = "this is a string"
  TheOtherString = "this is a long string that contains this is a string"
  </code></pre>
  
  <p>with linq I used something like:</p>
  
  <pre><code>from s in DB.Table 
  where TheOtherString.IndexOf(s.StringInDb ) &gt; -1
  select s.StringInDb;
  </code></pre>
  
  <p>How can I do this (efficiently) in mongodb (even better using the c# .net driver)?</p>