View source for Create a revision archive for field values

 {{howto|Expert|[[Olav B. Lygre]] <soppel at lygre dot no>}}

Describes how to create a revision system so every change in selected fields in a node can be tracked.

First create a table:

<code>
  CREATE TABLE IF NOT EXISTS `revision` (
  `rev_table` varchar( 50 ) NOT NULL ,
  `rev_field` varchar( 50 ) NOT NULL ,
  `rev_atkprimkey` varchar( 200 ) NOT NULL ,
  `rev_datetime` datetime NOT NULL ,
  `rev_username` varchar( 25 ) NOT NULL ,
  `rev_value` text,
  PRIMARY KEY ( `rev_table` , `rev_field` , `rev_datetime` , `rev_username` , `rev_atkprimkey` ))
</code>

Then use this baseclass instead of your usual atkNode.
Add fields from your node to 
$this->m_revision_fields(array("field1","field"));
Then every fieldchange in these fields will be saved to the database.
<syntaxhighlight lang="php">
  class watkNode extends atkNode {   
  var $m_revision_fields=array();  //Add fields from your node here to track changes
  function watkNode($type, $flags="")
    { 
    $this->atkNode($type, $flags);  
    if (count($this->m_revision_fields)>0)
      $this->addFlag(NF_TRACK_CHANGES);
    }
  function postUpdate($record)
    {
    if (count($this->m_revision_fields)>0)
      $this->checkrevision($record);  
    parent::postUpdate($record);
    return true;       
    }
  function postAdd($record)
    {
    if (count($this->m_revision_fields)>0)
      $this->checkrevision($record);  
    parent::postAdd($record);
    return true;       
    }
  function  checkrevision($record)
    {
    $save_revision_fields=array();
    foreach($this->m_revision_fields as $revision_field)
      if ($record[$revision_field]<>$record['atkorgrec'][$revision_field])
        $save_revision_fields[$revision_field]=$record[$revision_field];
    if (count($save_revision_fields)>0)
      $this->updaterevision($record['atkprimkey'],$save_revision_fields);
    $return;
    }
  function updaterevision($rev_atkprimkey,$save_revision_fields)
    {
    $revnode=&atkGetNode("revision.revision");
    global $g_user;
    $update_datetime=array('year'=>date('Y'),
         'month'=>date('m'),
         'day'=>date('d'),
         'hours'=>date('H'),
         'minutes'=>date('i'),
         'seconds'=>date('s')); 
         $rev_atkprimkey=str_replace("'","",$rev_atkprimkey);  //due to problems with ' in urls
    foreach($save_revision_fields as $field=>$value) {
      $attrib=$this->getAttribute($field); 
      $value=$attrib->display(array($field=>$value));
      $rec['rev_atkprimkey']=$rev_atkprimkey; 
      $rec['rev_table']=$this->m_table;
      $rec['rev_field']=$field;
      $rec['rev_username']=$g_user["full_name"];
      $rec['rev_datetime']= $update_datetime;
      $rec['rev_value']=$value;
      $revnode->addDb($rec); 
      unset($rec);
      }
    }
  }
</syntaxhighlight>

The revision node:

<syntaxhighlight lang="php">
  useattrib("atkattribute"); 
  useattrib("atkdatetimeattribute"); 
  useattrib("atktextattribute"); 
  class revision extends atkNode { 
    function revision()
    { $this->atkNode("revision",NF_ADD_LINK);
      $this->add(new atkAttribute("rev_atkprimkey", AF_SEARCHABLE|AF_PRIMARY));
      $this->add(new atkAttribute("rev_table", AF_SEARCHABLE|AF_PRIMARY));
      $this->add(new atkAttribute("rev_field", AF_SEARCHABLE|AF_PRIMARY));
      $this->add(new atkDateTimeAttribute("rev_datetime", AF_SEARCHABLE|AF_PRIMARY));
      $this->add(new atkAttribute("rev_username", AF_SEARCHABLE));
      $this->add(new atkTextAttribute("rev_value", AF_SEARCHABLE));          
       $this->setOrder("rev_table,rev_field,rev_datetime");
      $this->setTable("revision");
    }
  }
</syntaxhighlight>

What's missing here is a generic way of showing the different revisions.
An example of how this may look in the outlook theme is showed below.
This requires editing the edit & view handler, and the two templates.
[[Image:revision.gif]]