How is the binding of keys to different components or system elements implemented?

In PHP, binding keys to different components or system elements is often implemented through associative arrays or dependency injection containers.

For example, to store and access objects by key, an array can be used:

$components = [];

// Binding an object to a key
$components['database'] = new DatabaseConnection();

// Accessing the object by key
$db = $components['database'];

In more complex systems, a dependency container is used, which allows registering services by keys and retrieving them when needed, simplifying dependency management and increasing code modularity.