wpdb insert but update data if exist

$tableName = $wpdb->prefix."mengaji" ; 
		$data_update = array('user_id' => $user_id
		,'type_ngaji' => $wpdb->esc_like($_POST['type_ngaji']) 
		,'pengalaman' => $wpdb->esc_like($_POST['pengalaman'])  
		,'ajar_siapa' => $wpdb->esc_like(implode('#',$_POST['ajar_siapa']))  
		,'institusi_pengajian' => $wpdb->esc_like($_POST['institusi_pengajian'])  
		,'kemahiran_mengajar' => $wpdb->esc_like(implode('#',$_POST['kemahiran_mengajar']))  
		,'bahasa_pertuturan' => $wpdb->esc_like(implode('#',$_POST['bahasa_pertuturan']))  
		,'sekolah_ngaji' => $wpdb->esc_like($_POST['sekolah_ngaji'])  
		,'sekolah_pemilik' => $wpdb->esc_like($_POST['sekolah_pemilik'])  
		,'sekolah_nama' => $wpdb->esc_like($_POST['sekolah_nama'])  
		,'sekolah_no_pendaftaran' => $wpdb->esc_like($_POST['sekolah_no_pendaftaran'])  
		,'sekolah_jumlah_guru' => $wpdb->esc_like($_POST['sekolah_jumlah_guru'])  
		,'sekolah_guru_ngaji' => $wpdb->esc_like($_POST['sekolah_guru_ngaji'])  
		,'sekolah_atas_talian' => $wpdb->esc_like($_POST['sekolah_atas_talian'])  
		);
		$data_where = array('user_id' => $user_id);
		$result = $wpdb->update($tableName , $data_update, $data_where);
		//If nothing found to update, it will try and create the record.
		//print_r($data_where);print_r($result);exit();
		if ($result === FALSE || $result < 1) {
			$wpdb->insert($tableName, $data_update);
			$mengaji_id = $wpdb->insert_id;
		}