switch database limitation with PhpLib

[Anon]

Below is the code from db_mysql.inc, i had
modify the code to switch database :

/ public: connection management /
function connect($Database = "", $Host = "", $User = "", $Password = "") {

/* Handle defaults */
if ("" == $Database)
  $Database = $this->Database;
if ("" == $Host)
  $Host     = $this->Host;
if ("" == $User)
  $User     = $this->User;
if ("" == $Password)
  $Password = $this->Password;

/* establish connection, select database */
if ( 0 == $this->Link_ID ) {

  $this->Link_ID=mysql_pconnect($Host, $User, $Password);
  if (!$this->Link_ID) {
    $this->halt("pconnect($Host, $User, \$Password) failed.");
    return 0;
  }
}   

here the code i had change, bracket from

bottom already move to the top

I discover that $Database is lost in the if

function, anyone know what happen ??

   if (!@mysql_select_db($Database,$this->Link_ID)) {
    $this->halt("cannot use database ".$this->Database);
    return 0;
  }


return $this->Link_ID;

}

Following is the code i added to make it
works :

  $this->Database = $Database;

$this->Database = $Database; code added

  if (!@mysql_select_db($Database,$this->Link_ID)) {
    $this->halt("cannot use database ".$this->Database);
    return 0;
  }

Althougt it works, but i still dont know why
it's work. Any help ? the major problem is
$database value is lost.