moving from procedural code to oop - php

Question

Im relatively new to programming, with about 1 years part-time learning experience, im very new to PHP, only about a few weeks and using w3schools to help me
Im now trying to make the switch to OOP style and just cant understand the concept, or rather how and when to apply it and have thus turned here, where I have been a long time lurker instead of contributor for some help and advice.
I would like some help / short explanation how I would write the folloing in a PHP oop way
$sql="SELECT name, lastname, member_nr, joindate, order, creditCardInfo
from members
WHERE member_nr = $'member_nr'";
$result = mysql_query($sql) or die("error");
while($row = mysql_fetch_array){
echo '<h3>Personal Profile</h3>';
echo $name = $row['name'];
echo $lastName = $row['lastname'];
:
:
}
My problem is I dont know if I should create a class for the above, personal profile can be seen as a person right which is an object...? But do I include the HTML part and the mysql_query part etc in my class...Ive just got so many questions when it comes to OOP, its very hard to learn on your own thats why im really appreciate any drop of help or advice I can get on here
Thank you

Answer 1

First you should use mysqli, as all mysql_* are deprecated and are removed from PHP in the future.
Here a basis class with some functions, but you should expand it for your use! And learn what the functions do which got no comments on your own, to learn more.
This makes multiple connections to the database, so reading some stuff about singleton would be good for you too!
<?php
class dbconnection {
private $dbHostname;
private $dbName;
private $dbUsername;
private $dbUserpassword;
private $error;
private $querysuccess;
private $connected;
private $mysqli;
public function __construct() {
$this->dbHostname = 'localhost';
$this->dbName = 'databasename';
$this->dbUsername = 'username';
$this->dbUserpassword = 'password';
$this->connected = false;
}
public function __destruct() {
$this->mysqli->Close();
}
public function connect() {
//establishing a database connection
$this->mysqli = new mysqli($this->dbHostname, $this->dbUsername, $this->dbUserpassword, $this->dbName);
if($this->mysqli->connect_errno) {//When there was an error during the connecting
echo 'Connection Error:<br>'.$this->mysqli->connect_error;
$this->connected = false;
} else {
$this->connected = true;
}
if(!$this->mysqli->set_charset('utf8')) {//Need to be done for some functions!
echo 'Error during seting the charset: <br>'.$this->mysqli->error;
}
}
public function doquery($query_str) {
//method which executes the query
$returnval = false;
if($this->connected && $query_str != '') {
//only when connected AND the query is not empty
$res = $this->mysqli->query($query_str);//this is the equivalent of mysql_query
if($this->error_get() == '') {//Check for an error
$this->querysuccess = true;
} else {
$this->querysuccess = false;
}
$returnval = $res;
} else {
echo 'No database connection, this needs some!';
}
return $returnval;
}
public function query_success() {
return $this->querysuccess;
}
public function affected_rows_get() {
return $this->mysqli->affected_rows;
}
public function error_get() {
return $this->mysqli->error;
}
public function insert_id_get() {
return $this->mysqli->insert_id;
}
public function escape_str($str) {
return $this->mysqli->real_escape_string($str);
}
public function is_connected() {
return $this->connected;
}
public function fetch_assoc(&$res){
return $res->fetch_assoc();
}
public function fetch_assoc_array(&$res){
return $res->fetch_array(MYSQLI_ASSOC);
}
}

Answer 2

This case wouldn't be a good example. You want a class when you want to encapsulate logic of one entity to simplify its use outside the class.
For example:
class Member {
private $id, $name,
$lastname, $member_nr, $joindate, $order, $creditCardInfo;
public function __construct($id = 0) {
if($id != null) $this->loadFromDB();
}
private function loadFromDB() {
//Do db load here...
}
public function Update(){
//Do db update
}
public function Delete() {
//Do db delete...
}
public function GetFromMemberNR($nr) {
//Do select
}
//Additional Functions Verfication
}
In the end you'll have fairly complex code here. But to use it outside you just include the class's php file.
include 'member.php';
$member = new Member();
$member->GetFromMemberNR(2); //Does everything for you inside the function..
There are plenty of tools to help you do database operations easier, but that is the basis of OOP. The main idea is Encapsulation for reusability.