---------- php debug ----------
Server=localhost;DataBase=mysql;UserID=root;PassWord=123456
resource(5) of type (mysql result)

Output completed (1 sec consumed) - Normal Termination


class DBCLS
{


//debug 调试开关
var $debug = true;

//debuginfo 错误信息，调试信息
var $debuginfo = "debug informations:\r\n";

//db_server MySQL主机地址
var $db_server;

//db_name 数据库名
var $db_name;

//db_user 数据库用户名
var $db_user;

//db_passwd 密码
var $db_passwd;

//db_links 数据库连接
var $db_link;

//db_query_sql SQL语句
var $db_query_sql = "show tables";

//db_recordset 结果集，记录集
var $db_recordset;

//ready 就绪开关
var $conntstr_ready = false;
var $link_ready = false;
var $db_ready = false;

//set or return Connection String 返回，或者设定连接字符串
function connection_string($connstr="")
{
if("" == $connstr)
{
//如果没有参数传入，返回已有的连接字符
return "Server=".$this->db_server.";DataBase=".$this->db_name.";UserID=".$this->db_user.";PassWord=".$this->db_passwd;
}
else
{
//否则，解析连接字符，初始化变量
preg_match_all("|([a-zA-Z0-9]*)=([a-zA-Z0-9]*);*|", $connstr, $tmparr, PREG_PATTERN_ORDER);
$this->db_server = (strtolower($tmparr[1][0]) == "server")?$tmparr[2][0]:"";
$this->db_name = (strtolower($tmparr[1][1]) == "database")?$tmparr[2][1]:"";
$this->db_user = (strtolower($tmparr[1][2]) == "userid")?$tmparr[2][2]:"";
$this->db_passwd = (strtolower($tmparr[1][3]) == "password")?$tmparr[2][3]:"";
//var_dump($tmparr);

if("" == $this->db_server or "" == $this->db_name or "" == $this->db_user or "" == $this->db_passwd)
$this->conntstr_ready = false; //如果有其中一个以上变量被赋以空字符串"",准备未就绪
else
$this->conntstr_ready = true;
return $this->conntstr_ready;
}

}


//连接数据库，返回连接对象
function connect()
{
if(!$this->conntstr_ready)
{
if($this->debug){$this->debuginfo .= "连接字符串无效！\r\n";}
return $this->link_ready;
}
if($this->db_link = @mysql_connect($this->db_server, $this->db_user, $this->db_passwd))
{
$this->link_ready = true;
return $this->link_ready;
}
}


//选择数据库
function select($db = "")
{
if(!$this->db_link)
{
if($this->debug){$this->debuginfo .= "没有可用的数据库连接！\r\n";}
$this->db_ready = false;
}
if("" == $db)
{
if(mysql_select_db($this->db_name))
$this->db_ready = true;
}
if(mysql_select_db($this->db_name = $db))
$this->db_ready = true;
return $this->db_ready;
}


//执行查询
function execute($SQL = "")
{
if("" != $SQL)
{
$this->db_query_sql = $SQL;
//if($this->debug){$this->debuginfo .= "SQL is null!\r\n";}
//return false;
}
if("" == $this->db_query_sql)
{
if($this->debug){$this->debuginfo .= "SQL is null!\r\n";}
return false;
}
$this->db_recordset = mysql_query($this->db_query_sql);
return true;
}
}


$dbmy = new DBCLS(); //创建一个DBCLS对象
if(!$dbmy->connection_string("Server=localhost;DataBase=mysql;UserID=root;PassWord=123456"))//初始化DBCLS对象dbmy

print $dbmy->debuginfo; //初始化失败，输出错误信息

else

print $dbmy->connection_string(); //初始化成功，输出连接字符串
print "\r\n";

if(!($dbmy->connect()) or !($dbmy->select())) //如果连接数据库，或者选择数据库失败
print $dbmy->debuginfo; //输出出错信息
//$dbmy->db_query_sql = "select * from user";
if($dbmy->execute()) //执行查询指令
{ //如果不出错
var_dump($dbmy->db_recordset);//输出返回的结果集
}
?>

输出信息：

---------- php debug ----------
Server=localhost;DataBase=mysql;UserID=root;PassWord=123456
resource(5) of type (mysql result)

Output completed (1 sec consumed) - Normal Termination