title: When should I denormalise data in MySQL?
body: <p>I'm building a multi-currency application.</p>
  
  <p>Consider a post table with the following fields:</p>
  
  <pre><code>id, country_id, price
  </code></pre>
  
  <p>Every time I fetch the price field, I also need the currency to display it on the front-end. Therefore, I need to do two joins (or run 3 queries with laravel <code>with</code>) every time I try and get the post just to get the currency.</p>
  
  <pre><code>post-&gt;country-&gt;currency
  </code></pre>
  
  <p>To solve this, I could just store the currency in the post table. This, however, goes against normalisation guidelines. It also duplicates data across tables.</p>
  
  <p>Should I denormalise the data and store the currency in the post table?</p>