jorortega at gmail dot com (2012-07-12 19:04:59)

Be aware that, since the class fields get values assigned to them BEFORE the constructor is called, the...
if ($result = $mysqli->query($query)) {
...statement in some cases has not sense. At all.
Using some example:
$query = "SELECT * FROM City WHERE Country='some country'";
If 'some country' doesn't exist, $query won't be FALSE like with the good old days, but will be an object with some predefined fields. Thus, in this case, the if statement is useles, as it will always be TRUE.
In this case, is best to check the object property "num_rows" :
if ($result->num_rows != 0) ...
because if the query fails, num_rows will be asigned the number 0 (integer), and thus, you will know the query failed.

Driek (2012-06-26 17:18:46)

As indicated in the user comments of the mysql_fetch_object, it is important to realize that class fields get values assigned to them BEFORE the constructor is called.
For example;
<?php

class Employee
{
  private $id;

  public function __construct($id = 0)
  {
    $this->id = $id;
  }
}

// some code for creating a database connection... i.e. mysqli object
....
$result = $con->query("select id, name from employees");
$anEmployee = $result->fetch_object("Employee");
?>
will result in the ID being 0 because it is overridden by the constructor. Therefore, it is useful to check if the class field is already set.
I.e.
<?php
class Employee
{
  private $id;

  public function __construct($id = 0)
  {
    if (!$this->id)
    {
       $this->id = $id 
    }
  }
}
?>
Also note that the fields which will be assigned by fetch_object are case sensitive. If your table has the field "ID", it will result in the class field $ID being set. A simple work-around is to use aliases. I.e. "SELECT *, ID as id FROM myTable"
I hope this helps some people.

Alex (2012-01-27 04:36:32)

Make sure to specify the full namespace for the "string $class_name" parameter and not a partial one, as it won't find it. For example:

<?php

namespace Root(backslash)FirstLevel
{
    public static function Test($result)
    {
        return mysqli_fetch_object($result, 'SecondLevel\\MyClass');
    }
}

?>

... will not work but this will:

<?php

namespace Root(backslash)FirstLevel
{
    public static function Test($result)
    {
        return mysqli_fetch_object($result, 'Root\\FirstLevel\\SecondLevel\\MyClass');
    }
}

?>

benpptung at tacol dot biz (2009-08-08 20:04:09)

I don't know why no one talk about this.
fetch_object is very powerful since you can instantiate an Object which has the methods you wanna have.

You can try like this..

<?php
class PowerfulVO extends AbstractWhatEver {

    public $field1;
    private $field2; // note : private is ok

    public function method(){
       // method in this class
    }
}

     $sql = "SELECT * FROM table ..."
     $mysqli = new mysqli(........);
     $result = $mysqli->query($sql);
     $vo = $result->fetch_object('PowerfulVO');
?>

Note : if the field is not defined in the class, fetch_object will add this field for you as public.

The method is very powerful, especially if you want to use a VO design pattern or class mapping feature with Flex Remoting Object( Of course, you need to have ZendAMF or AMFPHP ..framework)

Hope this help and open new possibilities for you

peterbelm at g[oogle]mail dot com (2008-08-18 07:10:32)

If your SQL code selects columns with empty names like so:
SELECT id as ``...
You will get a fatal error "Cannot access empty property", this took me a while to track down!
Obviously your SQL really shouldn't do that, and should be fixed but I'm going to submit a feature request to ask for a better error message for that.