title: Database structure for product attributes on orders
body: <p>I'm making a POS and currently kind of stuck on the order proccess due to the product attributes.</p>
  
  <p>As of now the DB looks something like this:</p>
  
  <p><code>tbl_products</code></p>
  
  <p><code>tbl_attributes (attr id, name, extra price)</code></p>
  
  <p><code>tbl_sales ( where i store the time, total price etc)</code></p>
  
  <p><code>tbl_salelines ( where i store what items have being order for a certain sale).</code></p>
  
  <p>Problem is storing the attributes for an item order.
  There isn't a fix amount of attributes one item can have. It could go from 1 to 10-15
  therefor i don't think making some columns in the tbl_salelines with <code>attr_1</code> <code>attr_2</code> etc etc would solve this.</p>
  
  <p>How should i approach this?</p>