Fetching rows using PHP OO Class - php

Question

I have made a class function which will get rows from a table in my database along with an optional argument. This works when getting a single row however I cant get this to work when multiple rows are returned.
Here is what is in the Users class
public function getUsers($filter="") {
$Database = new Database();
if($filter == 'male')
$extra = "WHERE gender = 'm'";
$sql = "SELECT *
FROM users
$extra";
if ($Database->query($sql))
return $Database->result->fetch_assoc();
else
return false;
}
Database Class
class Database {
private $db = array();
private $connection;
private $result;
public function __construct() {
$this->connect();
}
public function connect() {
$this->connection = mysqli_connect('mysql.com', 'username', 'pass');
mysqli_select_db($this->connection, 'database');
}
public function query($sql) {
$this->result = mysqli_query($this->connection, $sql);
return $this->result;
}
This is the code used to try and display the rows
if ($student = $User->getUsers($filter)) {
echo "<table>\n";
echo "<tr><td>Col 1</td><td>Col 2</td><td>Col 3</td><td>Col 4</td><td></td><td></td></tr>";
foreach($student as $row) {
echo "<tr>";
echo "<td>$row[col1]</td>";
echo "<td>$row[col2]</td>";
echo "<td>$row[col3]</td>";
echo "<td>$row[col4]</td>";
echo "<td>$row[col5]</td>";
echo "<td>$row[col6]</td>";
echo "</tr>\n";
}
echo "</table>";
}
(I'm learning OO PHP, bear with me)

Answer 1

I'm still learning OOP but I have used this:
protected $connection, $result, $_numRows;
public function query($sql)
{
$this->result = mysql_query($sql, $this->connection);
$this->_numRows = mysql_num_rows($this->result);
}
/*
* #desc get result af query
*
* #returns string $result
*/
public function getResult()
{
return $this->result;
}
/*
* #desc Return rows in table
* #returns int $_numRows
*/
public function numRows()
{
return $this->_numRows;
}
/*
* #desc Count rows and add to array
* #return string $rows array
*/
public function rows()
{
$rows =array();
for ($x=0; $x < $this->numRows(); $x++) {
$rows[] = mysql_fetch_assoc($this->result);
}
return $rows;
}
Then you could use something like this to get the rows:
public function getUsers($filter="") {
$Database = new Database();
if($filter == 'male')
$extra = "WHERE gender = 'm'";
$sql = "SELECT *
FROM users
$extra";
if ($this->numRows() == 0) {
echo "No rows found";
} else {
foreach ($this->rows() as $b) {
$c = array('something' => $b['col']);
}
return $c;
}
Modify the last part to suit your needs.

Answer 2

It's not clear in your code where $result comes from...
You should call the fetch_assoc() method of an object returned by:
$mysqli->query($query)

Answer 3

Why are you using $result->fetch_assoc() twice? you are returning an array.. you should deal with $student.