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.
mysqli_result::fetch_object
mysqli_fetch_object
(PHP 5, PHP 7, PHP 8)
mysqli_result::fetch_object -- mysqli_fetch_object — Devuelve la fila actual de un conjunto de resultados como un objeto
Descripción
Estilo orientado a objetos
Estilo por procedimientos
mysqli_fetch_object(mysqli_result
$result, string $class_name = "stdClass", array $params = ?): objectmysqli_fetch_object() devolverá la fila actual del conjunto de resultados como un objeto, donde los atributos del objeto representan los nombres de los campos encontrados en el conjunto de resultados.
Observe que mysqli_fetch_object() establece las propiedades del objeto antes de llamar al constructor del objeto.
Parámetros
-
result -
Sólo estilo por procedimientos: Un conjunto de identificadores de resultados devuelto por mysqli_query(), mysqli_store_result() o mysqli_use_result().
-
class_name -
El nombre de la clase a instanciar, establecer las propiedades y devolver. Si no se especifica se devuelve un objeto stdClass.
-
params -
Un array opcional de parámetros para pasar al constructor de los objetos de
class_name.
Valores devueltos
Devuelve un objeto con las propiedades de cadena que corresponden a la fila
obtenida o null si no hay más filas en el conjunto de resultados.
Nota: Los nombres de los campos devueltos por esta función son sensibles a mayúsculas y minúsculas.
Nota: Esta función define campos NULOS al valor
nullde PHP.
Ejemplos
Ejemplo #1 Estilo orientado a objetos
<?php
$mysqli = new mysqli("localhost", "mi_usuario", "mi_contraseña", "world");
/* comprobar la conexión */
if (mysqli_connect_errno()) {
printf("Falló la conexión: %s\n", mysqli_connect_error());
exit();
}
$consulta = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($resultado = $mysqli->query($consulta)) {
/* obtener el array de objetos */
while ($obj = $resultado->fetch_object()) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* liberar el conjunto de resultados */
$resultado->close();
}
/* cerrar la conexión */
$mysqli->close();
?>Ejemplo #2 Estilo por procedimientos
<?php
$enlace = mysqli_connect("localhost", "mi_usuario", "mi_contraseña", "world");
/* comprobar la conexión */
if (mysqli_connect_errno()) {
printf("Falló la conexión: %s\n", mysqli_connect_error());
exit();
}
$consulta = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($resultado = mysqli_query($enlace, $consulta)) {
/* obtener el array asociativo */
while ($obj = mysqli_fetch_object($resultado)) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* liberar el conjunto de resultados */
mysqli_free_result($resultado);
}
/* cerrar la conexión */
mysqli_close($enlace);
?>El resultado de los ejemplos sería:
Pueblo (USA) Arvada (USA) Cape Coral (USA) Green Bay (USA) Santa Clara (USA)
Ver también
- mysqli_fetch_array() - Obtiene una fila de resultados como un array asociativo, numérico, o ambos
- mysqli_fetch_assoc() - Obtener una fila de resultado como un array asociativo
- mysqli_fetch_row() - Obtener una fila de resultados como un array enumerado
- mysqli_query() - Realiza una consulta a la base de datos
- mysqli_data_seek() - Ajustar el puntero de resultado a una fila arbitraria del resultado
add a note
User Contributed Notes 5 notes
Driek ¶
12 years ago
object-array at gmail dot com ¶
8 years ago
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
neo22s at gmail dot com ¶
8 years ago
Since 5.6.21 and PHP 7.0.6
mysqli_fetch_object() sets the properties of the object AFTER calling the object constructor. Not BEFORE as was in previous versions.
So behaviour has changed. Seems a bug but not sure if was done intentionally.
https://bugs.php.net/bug.php?id=72151
macole at paypal dot com ¶
8 years ago
Note that if you supply a class that has a __set() magic method defined in it, that method will be called for any properties that are not defined in your class. For example:
<?php
class SomeClass {
private $id;
public $partner_name;
public function __set( $name, $value ) {
echo "__set was called! Name = $name\n";
$this->$name = $value;
}
}
$db = new mysqli( 'localhost', 'Username', 'Password', 'DbName' );
$result = $db->query( 'SELECT id, partner_name, partner_type FROM submissions' );
$object = $result->fetch_object( 'SomeClass' );
?>
Produces the following output:
__set was called! Name = partner_type
benpptung at tacol dot biz ¶
15 years ago
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
