title: What is the difference between using TTimer and using TThread
body: <p>I have developed an application that connects to SQL Server database and reads some data from tables every 1 second.<br>
  For this purpose I use <code>TTimer</code> but the delay of the database response affects my application performance.</p>
  
  <p>I know a little about <code>TThread</code> in Delphi, what I want to know now is the difference between using <code>TTimer</code> and <code>TThread</code>? And using <code>TThread</code> instead of <code>TTimer</code> is useful for my application performance in this case?</p>