title: selecting a table in mysql
body: <p>I have a mysql database and some tables. </p>
  
  <p>One table is <strong>Products</strong>: Its columns are <code>prod_id</code>, <code>prod_type</code>. </p>
  
  <p><strong>Prod_types</strong> are <code>mobile</code> or <code>laptop</code> or <code>book</code>.</p>
  
  <p>Each of them have different attributes (eg: <em>publisher, author for books, battery_condition, model for laptop</em> etc). </p>
  
  <p>Should I <strong>store all the data</strong> in the <strong>Products</strong> table by adding columns like 'author', 'model' etc and keep null for those columns which don't apply to my product.</p>
  
  <p>For example for an entry with <code>prod_type='book'</code> , 'model', 'batter_condition' etc will be null. Or should I create different tables for 'book', 'mobile' and 'laptop' ?</p>