# PHP Late Static Binding

Late static binding comes from an internal feature of PHP that stores the class named in the last "non-forwarding call". In simpler terms, it allows you to reference the class that was actually called at runtime, rather than the class where the method is defined.

---

## 1. The Limitation of `self::`
Normally, `self::` refers to the class in which the code is written (compile-time resolution). This can be problematic when using inheritance.

```php
class Model {
    public static function getTableName() {
        return 'generic_model';
    }

    public static function select() {
        // self:: refers to Model, even if called from User
        echo "SELECT * FROM " . self::getTableName();
    }
}

class User extends Model {
    public static function getTableName() {
        return 'users';
    }
}

User::select(); // Outputs: SELECT * FROM generic_model
```

## 2. Using `static::` (Late Static Binding)
To fix this, PHP 5.3 introduced the `static::` keyword. It refers to the class that was initially called at runtime.

```php
class Model {
    public static function getTableName() {
        return 'generic_model';
    }

    public static function select() {
        // static:: refers to the class that called the method
        echo "SELECT * FROM " . static::getTableName();
    }
}

class User extends Model {
    public static function getTableName() {
        return 'users';
    }
}

User::select(); // Outputs: SELECT * FROM users
```

## 3. `self` vs `static`

| Keyword | Resolution Time | Refers To |
| :--- | :--- | :--- |
| `self::` | Compile Time | The class where the method is defined. |
| `static::` | Runtime | The class that invoked the method. |

[[programming/php/php]] [[programming/php/php-classes]]