PHP 7.1.0 Released

PDOStatement::fetchObject

(PHP 5 >= 5.1.0, PHP 7, PECL pdo >= 0.2.4)

PDOStatement::fetchObjectFetches the next row and returns it as an object.

Descrição

public mixed PDOStatement::fetchObject ([ string $class_name = "stdClass" [, array $ctor_args ]] )

Fetches the next row and returns it as an object. This function is an alternative to PDOStatement::fetch() with PDO::FETCH_CLASS or PDO::FETCH_OBJ style.

When an object is fetched, its properties are assigned from respective column values, and afterwards its constructor is invoked.

Parâmetros

class_name

Name of the created class.

ctor_args

Elements of this array are passed to the constructor.

Valor Retornado

Returns an instance of the required class with property names that correspond to the column names ou FALSE em caso de falha.

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User Contributed Notes 6 notes

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61
rasmus at mindplay dot dk
3 years ago
Be warned of the rather unorthodox behavior of PDOStatement::fetchObject() which injects property-values BEFORE invoking the constructor - in other words, if your class  initializes property-values to defaults in the constructor, you will be overwriting the values injected by fetchObject() !

A var_dump($this) in your __construct() method will reveal that property-values have been initialized prior to calling your constructor, so be careful.

For this reason, I strongly recommend hydrating your objects manually, after retrieving the data as an array, rather than trying to have PDO apply properties directly to your objects.

Clearly somebody thought they were being clever here - allowing you to access hydrated property-values from the constructor. Unfortunately, this is just not how OOP works - the constructor, by definition, is the first method called upon construction.

If you need to initialize your objects after they have been constructed and hydrated, I suggest your model types implement an interface with an init() method, and you data access layer invoke this method (if implemented) after hydrating.
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8
beinghavingbreackfast at gmail dot com
1 year ago
It should be mentioned that this method can set even non-public properties. It may sound strange but it can actually be very useful when creating an object based on mysql result.
Consider a User class:

<?php
class User {
  
// Private properties
  
private $id, $name;

   private function
__construct () {}

   public static function
load_by_id ($id) {
     
$stmt = $pdo->prepare('SELECT id, name FROM users WHERE id=?');
     
$stmt->execute([$id]);
      return
$stmt->fetchObject(__CLASS__);
   }
  
/* same method can be written with the "name" column/property */
}

$user = User::load_by_id(1);
var_dump($user);
?>

fetchObject() doesn't care about properties being public or not. It just passes the result to the object. Output is like:

object(User)#3 (2) {
  ["id":"User":private]=>
  string(1) "1"
  ["name":"User":private]=>
  string(10) "John Smith"
}
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1
zlk1214 at gmail dot com
9 months ago
You can access MySQL tables in an objective way. Suppose you have a table named Users that has fields: UserID, UserName, UserPassword, UserBirthday, you can create a PHP class extending DataObject that is associated with this table:
<?php
class User extends DataObject {
   
// name: Table Name, key: Primary Key (can be an array), auto: AUTO_INCREMENT field
   
protected static $_table = array('name' => 'Users', 'key' => 'UserID', 'auto' => 'UserID');
   
// relationships between PHP properties and MySQL field names
   
protected static $_propertyList = array('id' => 'UserID', 'name' => 'UserName', 'password' => 'UserPassword', 'birthday' => 'UserBirthday');
   
   
// A method that fetches all users as an array
   
public static function GetAll() {
        global
$dbh;
       
$sql = 'SELECT * FROM Users';
       
$stmt = $dbh->query($sql);
       
$users = array();
        while (
$user = $stmt->fetchObject(__CLASS__)) {
           
$users[] = $user;
        }
        return
$users;
    }
   
// Methods that fetch a specific user
   
public static function GetUserByName($name) {}
    public static function
GetUserByID($name) {}
   
   
// Methods for the current user object
   
public function checkPassword($password) {return $this->password == $password;}
    public function
showLink() {return "<a href=\"user.php?i={$this->id}\">{$this->name}</a>";}
}

// Then, you can create an instance of this class to insert a row in your table
$user = new User();
$user->name = 'oct1158';
$user->password = '789012';
$user->useFunction('birthday', 'NOW()');
echo
'Field birthday uses MySQL Function: ', $user->birthday, '<br>';
if (
$user->insert()) {
    echo
'New User ID: ', $user->id, '<br>';
   
   
// Update the row
   
$user->password = '112233';
   
$user->update();
} else {
    echo
'INSERT Failed<br>';
}
// Get a specific user by a query
$sql = 'SELECT * FROM Users WHERE UserName = ?';
$stmt = $dbh->prepare($sql);
$stmt->execute(array('admin'));
$admin_user = $stmt->fetchObject('User');
echo
'Admin ID is ', $admin_user->id, '.<br>';
echo
'Admin Birthday is ', $admin_user->birthday, '.<br>';

// Get all users by a static method of that class
$users = User::GetAll();
echo
'<br>';
echo
$users[0]->name, ', ', $users[0]->birthday, '<br>';
echo
$users[1]->name, ', ', $users[1]->birthday, '<br>';
echo
$users[2]->name, ', ', $users[2]->birthday, '<br>';
echo
'<br>';

// Create an empty user and then delete it immediately
$user = new User();
$user->insert();
$user->delete();
?>
The DataObject class example:
<?php
class DataObject {
    private
$changedFields = array(); // list of updated fields
   
private $data = array(); // original row from PDOStatement
   
private $funcFields = array(); // fields that use MySQL functions
    // The properties above are private in this class, so even if in your subclass you define some properties named the same, or you associate a property of the same name with a field in your table, they will never influence these properties.
   
function __get($property) {
        if (isset(
$this::$_propertyList[$property])) {
            return
$this->data[$this::$_propertyList[$property]]; // access fields by PHP properties
       
} else {
            return
$this->$property; // throw the default PHP error
       
}
    }
    function
__set($property, $value) {
        if (isset(
$this::$_propertyList[$property])) {
           
$field = $this::$_propertyList[$property];
           
$this->data[$field] = $value; // update $data
           
            // take down changed fields
           
if (!in_array($field, $this->changedFields)) {
               
array_push($this->changedFields, $field);
            }
           
$index = array_search($field, $this->funcFields);
            if (
$index !== false) {
                unset(
$this->funcFields[$index]);
               
$this->funcFields = array_values($this->funcFields);
            }
        } else {
           
// For fetchObject
           
$this->data[$property] = $value; // redirect to Array $data
       
}
    }
    private function
checkPrimaryKey() {}
    private function
clear() {}
    public function
delete() {}
    public function
insert() {}
    public function
update() {}
    public function
useFunction($property, $function) {}
}
?>
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4
dave at davidhbrown dot us
1 year ago
If using a namespaced class, you must provide the fully qualified class name; fetchObject does not seem to know about any "use" statements.

This results in a PHP Fatal error: Class 'MyClass' not found...:
<?php
use MyNamespace\MyClass;
// ...
$o = $statement->fetchObject('MyClass'));
?>
This works:
<?php
use MyNamespace\MyClass; //still needed for my code
// ...
$o = $statement->fetchObject('MyNamespace\\MyClass'));
?>
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-11
Anonymous
1 year ago
I think so could us use this variant to implement the constructor, this is my example:

<?php
class User{
    public
$user;
    public
$password;
    public
$name;
    public
$email;
   
    public function
__construct(){
       
$args = func_get_args();
       
$nargs = func_num_args();
       
$attribs = get_class_vars(get_class($this));
        if(isset(
$args)){
            foreach(
$args as $value){
               
$attrib = key($attribs);
               
$this->$attrib = $value;
               
next($attribs);
            }
        }
    }
}
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-21
Vegard Lkken
2 years ago
Because of the injection of object properties before the constructor is executed, I usually build my classes like this to make sure already set properties aren't overwritten:

<?php
class Person {
  public
$name;
  public
$age;
  public
$sex;

  public function
__construct($name=NULL, $age=NULL, $sex=NULL) {
   
$this->name = $name === NULL ? $this->name : $name;
   
$this->age = $age === NULL ? $this->age : $age;
   
$this->sex = $sex === NULL ? $this->sex : $sex;
  }
}
?>
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