title: MySQL storage : best way to archive data
body: <p>I'm quiet new in the SQL field. Thus I have a way of working question.</p>
  
  <p>Every week, I will send data from an Excel spreadsheet on my MySQL DB through a pHp code. This is already working. Thus I have a table which I can update.</p>
  
  <p>Actually I'm sending price of a specific underlying on my DB. What is the best way to archive my data as following.</p>
  
  <p>On my DB, I have the below structure :</p>
  
  <pre><code>tabe t_index
  Label = VARCHAR(255)
  Price = float
  Date = date()
  </code></pre>
  
  <p>Let's say I sent my data on my db last week, thus I stored :</p>
  
  <pre><code>Stock A
  102.85
  2013-03-18
  </code></pre>
  
  <p>Today, I want to send new price for the same <code>Stock A</code> which is <code>103.54</code>, but I would like to archive and keep the <code>102.85</code> price to be able to make some return or whatever between the two prices.</p>
  
  <p>How should I proceed ? </p>
  
  <p>I hope my question is not too messy... 
  Thank you for your help</p>