PHP DB-Klasse

<?
/**
 * DB Class
 *
 * THIS DB Class USE UTF-8!
 * FOR ISO CONNECTION COMMENT THIS ROW: $utf = $this->queryExecute("SET NAMES 'utf8'"); OUT! 
 *
 * DB Connect :
 * $db = new MyDb("localhost","dbuser","dbpass","dbname"); 
 *
 * Examples:
 *
 * only one result:
 * ----------------
 * if (($n = $db->querySingleItem("SELECT COUNT(*) FROM titles"))!=-1) { 
 *    printf("<p>Anzahl der Titel: %d</p>",$nr); 
 * }
 *
 * more results:
 * -------------
 * if ($result=$db->queryObjectArray("SELECT * FROM titles")) { 
 *    foreach ($result as $row) {
 *        printf("<br />TitleID:%d Title=%s Subtitle=%s\",$row->titleID,$row->title,$row->subtitle); 
 *    }
 * }
 *
 * count a select with affectedRows:
 * ---------------
 * if ($nr=$db->queryExecute("SELECT * FROM titles")) { 
 *    printf("<p>Anzahl der Titel: %d</p>",$nr); 
 * }
 *
 * execute a sql without result (only true/false returns)
 * -------------------------------------------------------
 * if ($result=$db->execute("UPDATE titles SET titel='my new Titel'")) { 
 *  echo "successful"; 
 * }
 *
 * if you like to see the short statistic use:
 * $db->showStatistics();
 * in your programm.
 *
 */

class MyDb {
    protected $mysqli;
    protected $showerror = true;   // set FALSE if you don't want to see error messages 
    protected $showsql   = false;  // set TRUE if you want to see all SQL queries for debugging purposes
    protected $sqlcounter = 0;     // counter for SQL commands
    protected $rowcounter = 0;     // counter for returned SELECT rows
    protected $dbtime     = 0;     // counter for time needed to execute queries
    protected $starttime;

    // constructor
    function __construct($dbhost, $dbuser, $dbpass, $dbname) {
        $this->mysqli = @new mysqli($dbhost, $dbuser, $dbpass, $dbname);
        // test, connect ok?
        if(mysqli_connect_errno()) {
            $this->printerror("Sorry, no connection! (" . mysqli_connect_error() . ")");  
            // you might add output for HTML code to close the page
            // here (</body></html> etc.)
            $this->mysqli = FALSE;
            exit();
        }
        // SET DB INTO UTF8 MODE
        $utf = $this->queryExecute("SET NAMES 'utf8'");  
        $this->starttime = $this->microtime_float();
    }

    // destructor
    function __destruct() {
        $this->close();
    }

    // explicit close
    function close() {
        if($this->mysqli)
        $this->mysqli->close();
        $this->mysqli = FALSE;
    }

    function getMysqli() {
        return $this->mysqli;
    }

    // execute SELECT query, return array
    function queryObjectArray($sql) {
        $this->sqlcounter++;
        $this->printsql($sql);
        $time1  = $this->microtime_float();
        $result = $this->mysqli->query($sql);
        $time2  = $this->microtime_float();
        $this->dbtime += ($time2 - $time1);
        if($result) {
            if($result->num_rows) {
                while($row = $result->fetch_object())
                $result_array = $row;
                $this->rowcounter += sizeof($result_array);
                return $result_array; }
                else
                return FALSE;
        } else {
            $this->printerror($this->mysqli->error);
            return FALSE;
        }
    }

    // execute SELECT query, return array
    function queryArray($sql) {
        $this->sqlcounter++;
        $this->printsql($sql);
        $time1  = $this->microtime_float();
        $result = $this->mysqli->query($sql);
        $time2  = $this->microtime_float();
        $this->dbtime += ($time2 - $time1);
        if($result) {
            if($result->num_rows) {
                while($row = $result->fetch_array())
                $result_array = $row;
                $this->rowcounter += sizeof($result_array);
                return $result_array;
            }else {
                return FALSE;
            }
        } else {
            $this->printerror($this->mysqli->error);
            return FALSE;
        }
    }


    // execute a SELECT query which returns only a single
    // item (i.e. SELECT COUNT(*) FROM table); return
    // this item
    // beware: this method return -1 for errors (not 0)!
    function querySingleItem($sql) {
        $this->sqlcounter++;
        $this->printsql($sql);
        $time1  = $this->microtime_float();
        $result = $this->mysqli->query($sql);
        $time2  = $this->microtime_float();
        $this->dbtime += ($time2 - $time1);
        if($result) {
            if ($row=$result->fetch_array()) {
                $result->close();
                $this->rowcounter++;
                return $row;
            } else {
                // query returned no data
                return -1;
            }
        } else {
            $this->printerror($this->mysqli->error);
            return -1;
        }
    }

    // execute a SQL command with the number of affected rows as results (no query)
    function queryExecute($sql) {
        $this->sqlcounter++;
        $this->printsql($sql);
        $time1  = $this->microtime_float();
        $result = $this->mysqli->real_query($sql);
        $time2  = $this->microtime_float();
        $this->dbtime += ($time2 - $time1);
        if($result) {
            // return TRUE;
            return $this->mysqli->affected_rows;
        } else {
            $this->printerror($this->mysqli->error);
            return FALSE;
        }
    }

    // execute a SQL command without results, only true/false (no query)
    function execute($sql) {
        $this->sqlcounter++;
        $this->printsql($sql);
        $time1  = $this->microtime_float();
        $result = $this->mysqli->real_query($sql);
        $time2  = $this->microtime_float();
        $this->dbtime += ($time2 - $time1);
        if($result) {
            return TRUE;
        } else {
            $this->printerror($this->mysqli->error);
            return FALSE;
        }
    }


    // get insert_id after an INSERT command
    function insertId() {
        return $this->mysqli->insert_id;
    }

    // get the number of affected rows after query command
    function affectedRows() {
        return $this->mysqli->affected_rows;
    }

    // get mysql system status
    function mysqlStats() {
        return $this->mysqli->stat();
    }

    // insert \ before ', " etc. 
    function escape($txt) {
        return trim($this->mysqli->escape_string($txt));
    }

    // return 'NULL' or '<quoted string>' 
    function sql_string($txt) {
        if(!$txt || trim($txt)=="")  
        return 'NULL';  
        else
        return "'" . $this->escape(trim($txt)) . "'";  
    }

    function error() {
        return $this->mysqli->error;
    }

    private function printsql($sql) {
        if($this->showsql)
        printf("<p><font color=\"#0000ff\">%s</font></p>\n",  
        htmlspecialchars($sql));
    }

    private function printerror($txt) {
        if($this->showerror)
        printf("<p><font color=\"#ff0000\">%s</font></p>\n",  
        htmlspecialchars($txt));
    }

    function showStatistics() {
        $totalTime = $this->microtime_float() - $this->starttime;
        printf("<p><font color=\"#0000ff\">SQL commands: %d\n",  
        $this->sqlcounter);
        printf("<br />Sum of returned rows: %d\n",  
        $this->rowcounter);
        printf("<br />Sum of query time (MySQL): %f\n",  
        $this->dbtime);
        printf("<br />Processing time (PHP): %f\n",  
        $totalTime - $this->dbtime);
        printf("<br />Total time since MyDB creation / last reset: %f</font></p>\n",  
        $totalTime);
    }

    function resetStatistics() {
        $this->sqlcounter = 0;
        $this->rowcounter = 0;
        $this->dbtime     = 0;
        $this->starttime = $this->microtime_float();  }

        private function microtime_float() {
            list($usec, $sec) = explode(" ", microtime());  
            return ((float)$usec + (float)$sec);
        }

}
?>