How to keep a controller item in static part of the page?

Question

It’s the following guys, I have a page of the project that serves as a standard for all the others, a Layout.. However I wish to add an item (informative) in it, and it only remains on the home page and in the CRUD of the informative, when it goes to other pages that occurs the controller exchange, gives error and the informative disappear. Could someone help??

layout page:

<div class="col-md-8">
    <div id="c-slide" class="carousel slide auto panel">

        <div class="carousel-inner">
            <?php foreach ($informativos as $index => $informativo){ ?>

                <div class="item text-center<?php echo ($index === 0 ? " active" : "") ?>" style="width: 90%;margin-left:5%">
                    <div class="alert alert-block alert-<?php echo $informativo['Informativo']['tipo']; ?> fade in">                                    
                        <?php echo $informativo['Informativo']['texto']; ?>
                    </div>
                </div>                        

            <?php } ?>
        </div>
        <a data-slide="prev" href="#c-slide" class="left carousel-control">
            <i class="fa fa-angle-left"></i>
        </a>
        <a id="nextInformativo" data-slide="next" href="#c-slide" class="right carousel-control">
            <i class="fa fa-angle-right"></i>
        </a>
    </div>
</div>

App Controller:

public $helpers = array(
        'Gravatar.Gravatar',
        'Html', 
        'Form', 
        'Session'
);

public $components = array(
        'Auth' => array(
                'authenticate' => array('Saml.Saml')
        ),
        'Session',
        'Cookie');

var $uses = array('User');

public function beforeFilter() {
    parent::beforeFilter();     

    $this->set('convertTime', $this->convertTime);

    if ($this->Saml){
        if ($this->Saml->isAuthenticated()) {               
            $infoWSO2 = $this->Saml->getAttributes();

            if($this->Session->read('UsuarioLogado') == NULL){
                 $userSistema = $this->User->atualizaSessao($infoWSO2);

                 $this->Session->write('UsuarioLogado', $userSistema);
            }

            $this->set('login_user', $infoWSO2);
        }
    }
}

Answer 1

You should make your query in the bank in Appcontroller, more or less like this:

public function beforeRender() {

    // sua query
    $query = array(
        'order' => array(
            ...
        ),
        'conditions' => array(
            ...
        ),
        'recursive' => 1
    );

    $data = $this->SeuModel->find('all', $query);
    $this->set(compact('data'));
}

So it will be available in all views.

It is not a practice considered correct, because you will have this query in all your controllers and actions, and may cause a certain slowness in your application.

Most correct, would be you save this data to a Session, and query it in the view, so it would not impact the database.