(PHP 5, PHP 7)
mysqli_result::fetch_object -- mysqli_fetch_object — Returns the current row of a result set as an object
Object oriented style
$class_name = "stdClass"
[, array $params
]] )Procedural style
$result
[, string $class_name = "stdClass"
[, array $params
]] )The mysqli_fetch_object() will return the current row result set as an object where the attributes of the object represent the names of the fields found within the result set.
Note that mysqli_fetch_object() sets the properties of the object before calling the object constructor.
resultProcedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
class_nameThe name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.
params
An optional array of parameters to pass to the constructor
for class_name objects.
Returns an object with string properties that corresponds to the fetched
row or NULL if there are no more rows in resultset.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = $mysqli->query($query)) {
/* fetch object array */
while ($obj = $result->fetch_object()) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* free result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = mysqli_query($link, $query)) {
/* fetch associative array */
while ($obj = mysqli_fetch_object($result)) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* free result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Pueblo (USA) Arvada (USA) Cape Coral (USA) Green Bay (USA) Santa Clara (USA)
Please mind the difference between objects and arrays in PHP>=5: arrays are by value while objects are by reference.
<?
$o = mysqli_fetch_object($res);
$o1 = $o;
$o1->value = 10;
$a = mysqli_fetch_array($res);
$a1 = $a;
$a1['value'] = 10;
echo $o->value; // 10
echo $a['value']; // (original value from db)
?>
Should same behaviour be intended, the object needs to be cloned:
<?
$o1 = clone $o;
?>
More about object cloning:
http://php.net/manual/en/language.oop5.cloning.php
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.
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
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');
}
}
?>
As a best practice, if you intend to use a defined class when using fetching_object(). Put the data obtaining code within a static method of the defined class. Otherwise, wherever you include the file (if not using an autoloader) the data connection will occur whether you want it to or not.
For example:
<?php
class User
{
public $name;
public static function getUser($id)
{
$conn = new mysqli('localhost', 'username', 'password', 'database');
if ($result = $conn->query("SELECT * FROM users WHERE id = {$id} LIMIT 1")) {
return $result->fetch_object('User');
$result->close();
}
}
}
?>
Call the static method to obtain an instance of the User class with your data applied to it.
<?php
$user = User::getUser('31');
echo $user->name; // echo's 'Phil'
?>
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.
