Помогите разобраться с классами cms

class MySQL {

// SET THESE VALUES TO MATCH YOUR DATA CONNECTION
private $db_host = ""; // server name
private $db_user = ""; // user name
private $db_pass = ""; // password
private $db_dbname = ""; // database name
private $db_charset = ""; // optional character set (i.e. utf8)
private $db_pcon = false; // use persistent connection?

// class-internal variables - do not change
private $error_desc = ""; // mysql error string
private $error_number = 0; // mysql error number
private $mysql_link = 0; // mysql link resource
private $count_query = 0; // mysql count query
private $delta = 0; // mysql time query
private $sql = ""; // mysql query
private $result; // mysql query result
private $data = array(); // placeholders
private $debug_info = array(); // debug_info

/**
* Determines if an error throws an exception
*
* @var boolean Set to true to throw error exceptions
*/
public $ThrowExceptions = true;

/**
* Constructor: Opens the connection to the database
*
* @param boolean $connect (Optional) Auto-connect when object is created
* @param string $database (Optional) Database name
* @param string $server (Optional) Host address
* @param string $username (Optional) User name
* @param string $password (Optional) Password
* @param string $charset (Optional) Character set
*/

function __construct($server="", $username="", $password="", $database="", $charset="", $pcon=false) {

if ($pcon) $this->db_pcon = true;
if (strlen($server) > 0) $this->db_host = $server;
if (strlen($username) > 0) $this->db_user = $username;
if (strlen($password) > 0) $this->db_pass = $password;
if (strlen($database) > 0) $this->db_dbname = $database;
if (strlen($charset) > 0) $this->db_charset = $charset;

//
if (strlen($this->db_host) > 0 && strlen($this->db_user) > 0)
{
$this->Open();
}
}

/**
* Connect to specified MySQL server
*
* @return boolean Returns TRUE on success or FALSE on error
*/






private function Open() {
$this->ResetError();

// Open persistent or normal connection
if ($this->db_pcon) {
$this->mysql_link = @mysql_pconnect($this->db_host, $this->db_user, $this->db_pass);
} else {
$this->mysql_link = @mysql_connect ($this->db_host, $this->db_user, $this->db_pass);
}

// Connect to mysql server failed?
if (! $this->IsConnected()) {
$this->SetError();
return false;
}
else // Connected to mysql server
{
// Select a database (if specified)
if (strlen($this->db_dbname) > 0) {
if (strlen($this->db_charset) == 0) {
if (! $this->SelectDatabase($this->db_dbname)) {
return false;
} else {
return true;
}
} else {
if (! $this->SelectDatabase($this->db_dbname, $this->db_charset)) {
return false;
} else {
return true;
}
}
} else {
return true;
}
}
}

/**
* Executes the given SQL query and returns the result
*
* @param string $sql The query string
* @return (boolean, string, object, array with objects) result
*/

public function Query($sql, $data = array()) {
$sql = $this->query_process($sql, $data);
$this->count_query++;
$this->ResetError();
$this->sql = $sql;
$xtime = microtime();
$this->result = @mysql_query($this->sql, $this->mysql_link);
// show debug info
if($debug) self::SaveDebugInfo("sql=".$this->sql);
// start the analysis
if (TRUE === $this->result) { // simply result
$return = TRUE; // successfully (for example: INSERT INTO ...)
} else if (FALSE === $this->result) {
$this->SetError();
if($debug) {
self::SaveDebugInfo("error=".$this->error_desc);
self::SaveDebugInfo("number=".$this->error_number);
}
$return = FALSE; // error occured (for example: syntax error)
}
else // complex result
{
$num_result = mysql_num_rows($this->result);

switch( $num_result )
{
case 0:
$return = NULL; // return NULL rows
break;
case 1: // return one row ...
if(1 != mysql_num_fields( $this->result))
{
$return = array();
while( $obj = mysql_fetch_object($this->result)) array_push($return, $obj);
}
else
{
$row = mysql_fetch_row($this->result); // or as single value
$return = $row[0];
}
break;
default:
$return = array();
while( $obj = mysql_fetch_object($this->result)) array_push($return, $obj);
}
}
$ytime = microtime();
$this->delta += array_sum(explode(' ',$ytime)) - array_sum(explode(' ',$xtime));

return $return;
}

/**
* Show count query
*/

public function CountQuery() {
return $this->count_query;
}

/**
* Show time query
*/

public function DeltaQuery() {
return $this->delta;
}

/**
* Show number of affected rows in previous operation
*/

public function Affected() {
return mysql_affected_rows($this->mysql_link);
}

/**
* Show last insert ID
*/

public function LastInsertID() {
return mysql_insert_id($this->mysql_link);
}

/**
* Determines if a valid connection to the database exists
*
* @return boolean TRUE idf connectect or FALSE if not connected
*/

public function IsConnected() {
if(isset($this->mysql_link))
{
if (gettype($this->mysql_link) == "resource") {
return true;
}
}

return false;
}

/**
* Selects a different database and character set
*
* @param string $database Database name
* @param string $charset (Optional) Character set (i.e. utf8)
* @return boolean Returns TRUE on success or FALSE on error
*/

public function SelectDatabase($database, $charset = "") {
$return_value = true;
if (! $charset) $charset = $this->db_charset;
$this->ResetError();
if (! (mysql_select_db($database))) {
$this->SetError();
$return_value = false;
} else {
if ((strlen($charset) > 0)) {
if (! (mysql_query("SET NAMES {$charset}", $this->mysql_link))) {
$this->SetError();
$return_value = false;
}
}
}
return $return_value;
}

/**
* Clears the internal variables from any error information
*
*/

private function ResetError() {
$this->error_desc = '';
$this->error_number = 0;
}

/**
* Save debug info
*/
private function SaveDebugInfo($string="") {
$this->debug_info[] = date("H:i:s").": ---".$string."---<br />";
}

/**
* Show debug info
*/
public function ShowDebugInfo() {
return $this->debug_info;
}

/**
* Sets the local variables with the last error information
*
* @param string $errorMessage The error description
* @param integer $errorNumber The error number
*/

private function SetError($errorMessage = '', $errorNumber = 0) {
try {
// get/set error message
if (strlen($errorMessage) > 0) {
$this->error_desc = $errorMessage;
} else {
if ($this->IsConnected()) {
$this->error_desc = mysql_error($this->mysql_link);
} else {
$this->error_desc = mysql_error();
}
}

// get/set error number
if ($errorNumber <> 0) {
$this->error_number = $errorNumber;
} else {
if ($this->IsConnected()) {
$this->error_number = @mysql_errno($this->mysql_link);
} else {
$this->error_number = @mysql_errno();
}
}
} catch(Exception $e) {
$this->error_desc = $e->getMessage();
$this->error_number = -999;
}

if ($this->ThrowExceptions && $this->error_number <> 0) {
throw new Exception($this->error_desc);
}
}

/**
* Destructor: Closes the connection to the database
*
*/

public function __destruct() {
$this->Close();
}

/**
* Close current MySQL connection
*
* @return object Returns TRUE on success or FALSE on error
*/

public function Close() {
$this->ResetError();
$success = $this->Release();
if ($success) {
$success = @mysql_close($this->mysql_link);
if (!$success) {
$this->SetError();
} else {
unset($this->sql);
unset($this->result);
unset($this->mysql_link);
}
}
return $success;
}

/**
* Frees memory used by the query results and returns the function result
*
* @return boolean Returns TRUE on success or FALSE on failure
*/

public function Release() {
$this->ResetError();
if (!isset($this->result)) {
$success = true;
} else {
if (!$this->result) {
$success = true;
} else {
$success = @mysql_free_result($this->result);
if (!$success) $this->SetError();
}
}
return $success;
}

private function holders_replace($matches) {
$placeholder = $matches[1];

if(is_array($this->data[$placeholder])) {
$data = array();
foreach($this->data[$placeholder] as $v) $data[] = mysql_real_escape_string($v);
$value = implode("', '", $data);
} else {
$value = mysql_real_escape_string($this->data[$placeholder]);
}
return "{$value}";
}

private function query_process($query, $data) {
$this->data = $data;

$query = preg_replace_callback("#{([^}]+)}#sUi", array($this, 'holders_replace'), $query);
return $query;
}
}