Let’s say that we want to prevent updates to any records in a particular table that are older than 30 days. To do so, we would customize the tablename_before_update() hooks like this:

function tablename_before_update(&$data, $memberInfo, &$args){
    // get the creation date of the record
    $creationDate=sqlValue("select dateAdded from membership_userrecords
      where tableName='tablename' and pkValue='{$data['selectedID']}'");
    // if the record is older than 30 days, deny changes
    if($creationDate < strtotime('30 days ago')) return false;
    return true;