title: Keeping page changes history. A bit like SO does for revisions
body: <p>I have a CMS system that stores data across tables like this:</p>
  
  <pre><code>Entries Table
  +----+-------+------+--------+--------+
  | id | title | text | index1 | index2 |
  +----+-------+------+--------+--------+
  
  Entries META Table
  +----+----------+-------+-------+
  | id | entry_id | value | param |
  +----+----------+-------+-------+
  
  Files Table
  +----+----------+----------+
  | id | entry_id | filename |
  +----+----------+----------+
  
  Entries-to-Tags Table
  +----+----------+--------+
  | id | entry_id | tag_id |
  +----+----------+--------+
  
  Tags Table
  +----+-----+
  | id | tag |
  +----+-----+
  </code></pre>
  
  <p>I am in trying to implement a revision system, a bit like SO has. If I was just doing it for the <code>Entries Table</code> I was planning to just keep a copy of all changes to that table in a separate table. As I have to do it for at least 4 tables (the TAGS table doesn't need to have revisions) this doesn't seem at all like an elegant solution.</p>
  
  <p><strong>How would you guys do it?</strong></p>
  
  <p>Please notice that the <strong><i>Meta Tables</i></strong> are modeled in <a href="http://en.wikipedia.org/wiki/Entity-attribute-value_model" rel="noreferrer"><strong>EAV</strong> (entity-attribute-value)</a>.</p>
  
  <p>Thank you in advance.</p>