title: Extract & transform data from Sql Server to MongoDB periodically
body: <p>I have a Sql Server database which is used to store data coming from a lot of  different sources (writers).</p>
  
  <p>I need to provide users with some aggregated data, however in Sql Server this data is stored in several different tables and querying it is too slow ( 5 tables join with several million rows in each table, one-to-many ).</p>
  
  <p>I'm currently thinking that the best way is to extract data, transform it and store it in a separate database (let's say MongoDB, since it will be used only for read).</p>
  
  <p>I don't need the data to be live, just not older that 24 hours compared to the 'master' database.</p>
  
  <p>But what's the best way to achieve this? Can you recommend any tools for it (preferably free) or is it better to write your own piece of software and schedule it to run periodically?</p>