/// <summary>
/// Updates the global last modified date for the site.
/// </summary>
/// <param name="tx">Optional transaction</param>
public static void SetSiteLastModified(IDbTransaction tx = null)
{
SysParam.Execute("UPDATE sysparam SET sysparam_value = @0 WHERE sysparam_name = @1", tx,
DateTime.Now, "SITE_LAST_MODIFIED");
SysParam.InvalidateParam("SITE_LAST_MODIFIED");
}