A problem in OOP

[milanello72]

Hello! I'm trying to learn OOP and I studying this example from phpacademy: http://www.youtube.com/watch?v=Ny4IJwyZKwo

 

But this code has an error:

[b]Notice[/b]: Undefined property: Database::$numRows in [b]C:\Program Files (x86)\EasyPHP-5.3.7.0\www\work\php academy\index.php[/b] on line [b]7[/b]
No books!

 

The line 7 in index.php is

if ($db->numRows == 0) {

 

The code from index.php

require_once('classes/database.php');

$db=new Database('localhost', 'root', '', 'librarie');

$db->query("select titlu from carti");
if ($db->numRows == 0) {
 echo 'No books!';
}
else {
  foreach ($db->rows() as $carte) {
   echo $carte['titlu'], '<br>';
  }
  echo '<p>', $db->numRows(), ' carti </p>';


}

$db->disconnect();

 

and the code from database.php

class Database {
 protected $_link, $_result, $_numRows;

 public function __construct($server, $username, $password, $db) {
   $this->_link=mysql_connect($server, $username, $password);
   mysql_select_db($db, $this->_link);
 }

 public function disconnect() {
 mysql_close($this->_link);
 }

 public function query($sql) {
 $this->_result=mysql_query($sql, $this->_link);
    $this->_numRows=mysql_num_rows($this->_result);     
 }

 public function numRows() {
   $this->_numRows;
 } 

 public function rows() {
   $rows=array();

   for ($x=0; $x < $this->_numRows(); $x++) {
   $rows[] = mysql_fetch_assoc($this->_result);
   }   
   return $rows;
 }
}

 

So, what can I do? Thank you very much for your help!

[Jessica]

1. You have a property _numRows and a function numRows(). You don't have a property numRows.

2. If you're trying to call the function numRows() you're going to have a problem in that your function doesn't do anything. Try return;

[jazzman1]

You have numRows() method not numRows.

 

if ($db->numRows == 0)

[milanello72]

I have put

return $this->_numRows;

, but it is the same error...

[Jessica]

Did you read the entire reply I gave?

[milanello72]

I have put and

if ($db->numRows() == 0)

and it is

Fatal error: Call to undefined method Database::_numRows() in C:\Program Files (x86)\EasyPHP-5.3.7.0\www\work\php academy\classes\database.php on line 27

[Jessica]

That line of code is not causing that error.

 

Try to do a little debugging on your own now. It tells you where the problem is and exactly what is wrong.

[jazzman1]

Fatal error: ?

What's your updated Database class?

[milanello72]

i have put in database.php

class Database {
 protected $_link, $_result, $_numRows;

 public function __construct($server, $username, $password, $db) {
   $this->_link=mysql_connect($server, $username, $password);
   mysql_select_db($db, $this->_link);
 }

 public function disconnect() {
 mysql_close($this->_link);
 }

 public function query($sql) {
 $this->_result=mysql_query($sql, $this->_link);
    $this->_numRows=mysql_num_rows($this->_result);     
 }

 public function numRows() {
   return $this->_numRows;

 } 

 public function rows() {
   $rows=array();

   for ($x=0; $x < $this->_numRows; $x++) {
   $rows[] = mysql_fetch_assoc($this->_result);
   }   
   return $rows;
 }
}

This code works!

thank you very much for your help!

[Jessica]

Good job.