PHP - Do Namespaces Exist In Php?

i have error where my code should update existing data where id exist, it get updated ..but the others data is disappeared .only the data updated is remained 

$sql1 ="select*from semakan_dokumen where email='$stdEmail'";
$sqlsearch1 = mysqli_query($dbconfig,$sql1);
$resultcount1 = mysqli_num_rows($sqlsearch1);

if($resultcount1 > 0){
$query1=("UPDATE  semakan_dokumen set student_id='$noMatrik', email= '$stdEmail', surat_tawaran='$fileName', ic='$fileName1',sijil_lahir='$fileName2',sijil_spm= '$fileName3',sijil_sekolah= '$fileName4', sijil_dip= '$fileName5',sej_julai='$fileName6',bm_julai='$fileName7',muet='$fileName8', mid1='$fileName9',yuran= '$fileName10',umpa_bend1= '$fileName11',umpa_bend2='$fileName12',bpkp='$fileName13', penaja='$fileName14',kesihatan= '$fileName15', jhepa='$fileName16' where email= '$stdEmail' ");

}else{


//filezip
$query1 = "INSERT INTO semakan_dokumen (email,surat_tawaran,ic,sijil_lahir,sijil_spm,sijil_sekolah,sijil_dip,sej_julai,bm_julai,muet,mid1,yuran,umpa_bend1,umpa_bend2,bpkp,penaja,kesihatan,jhepa) VALUES ('$stdEmail','$fileName','$fileName1','$fileName2','$fileName3','$fileName4','$fileName5','$fileName6','$fileName7','$fileName8','$fileName9','$fileName10','$fileName11','$fileName12','$fileName13','$fileName14','$fileName15','$fileName16')";
}

namespace lesson_one;
abstract class Lesson {

    protected $duration;
    const  FIXED = 1;
    const TIMED  = 2;
    private $costtype;

    function  __construct($duration, $costtype=1) {
        $this->duration = $duration;
        $this->costtype = $costtype;
    }

    function cost(){
        switch($this->costtype) {
            case self::TIMED:

        return (5* $this->duration);
        break;

       case self::FIXED:
        return 30;
        break;

       default:
       $this->costtype = self::FIXED;
        return 30;
        }

    }


    function chargeType() {
        switch($this->costtype) {
            case SELF::TIMED:
            return "hourly rate";
            break;


            case self::FIXED :
             return "fixed rate";
            break;

            default:
            $this->costtype = self::FIXED;
            return "fixed rate";
        }
    }

}


class Lecture extends  Lesson {

}

class Seminar extends Lesson {

}


//echo Lesson::FIXED;


$lecture = new \lesson_one\Lecture("5", Lesson1::FIXED);
echo $lecture->cost(). "<br>";
echo $lecture->chargeType(). "<br>";

get_class($this)

I have to be doing something wrong here, but so far Googling hasn't helped.  Take a look he

https://demo.envrin.com/api/classes/apex.app.msg.emailer.html#method_send

The doc-block is correct, or at least as far as I can tell it is, character-by-character.  I'm blind though, but have tried different combinations of things like "String" instead of "string" or "@Param" instead of "@param".  Made sure the ends of the @param lines ende din a period, and that seemed to help a little.

Nonetheless, why does it keep adding the namespace to everything in front of "string" like that?  Any why are the paramaters section all screwed up?

Any help would be appreciated.  Thanks!
 

# Resides within class.DataTypeBase.php
namespace DTB\Base;
class DataTypeBase {

    protected $name = '';

    protected function getName() {
        return $this->name;
    }

    protected function setName($name) {
        $this->name = $name;
    }
}


# Resides within class.DataType.php
namespace DTB;
class DataType extends DataTypeBase {

    public function process_data(){
        ....
    }
}

# Resides within class.DataTypes.php
namespace DataTypes;

class Silver extends DataType {
    
    public function differ($type) {
        ....
    }
}