Data paging in the Yii framework: Optimizing data display

With the rapid development of the Internet, the growth rate of data is also getting faster and faster. In web applications, data paging is one of the necessary tools to improve user experience. In the Yii framework, data paging is easy to implement. This article will introduce data paging in the Yii framework and how to optimize data display when the amount of data is large.

1. Data paging in the Yii framework

1.1 Paging class

In the Yii framework, the paging function is encapsulated in the CPagination class. The CPagination class provides the following common methods:

• setPageVar: Set the paging parameter name, the default is 'page';
• getPageCount: Get the total number of pages;
• getItemCount : Get the number of data items;
• getLimitOffset: Get the LIMIT... OFFSET... statement;
• getPages: Get the paging HTML code.

1.2 Using CPagination

Suppose we have a user model User, which has 10,000 pieces of data that need to be displayed in pages. First, we need to instantiate the CPagination object in the actionIndex method in UserController:

$pagination = new CPagination(10000);

Then, we can set the amount of data for each page:

$pagination->pageSize = 20;

Or use the default value:

$pagination->pageSize = Yii::app()->user-> ;pageSize;

Next, we need to calculate the current page number:

$pagination->setCurrentPage($_GET['page']);

Finally, we The data to be displayed needs to be obtained based on the current page number and the amount of data on each page:

$users = User::model()->findAll(array(

'limit' => $pagination->getLimit(),
'offset' => $pagination->getOffset(),

));

Finally, we also need to use the getPages method in the view file to obtain the paging HTML code:

<?php $this->widget('CLinkPager', array(
    'pages' => $pagination,
)); ?>

2. Optimize data display

When the amount of data is large, conventional paging methods may cause page loading to be slow and user experience to be degraded. Here are two ways to optimize data display.

2.1 Ajax paging

Using Ajax paging can avoid the problem of refreshing the entire page every time you switch pages. When the user clicks on the paging link, an Ajax request is sent to update only the part that needs to be updated, greatly increasing the page refresh speed.

$pagination = new CPagination(10000);
$pagination->pageSize = 20;
$pagination->setCurrentPage($_GET['page']);

$this->render('index', array(

'users' => User::model()->findAll(array(
    'limit' => $pagination->getLimit(),
    'offset' => $pagination->getOffset(),
)),
'pagination' => $pagination,

));

In the view file, we use yii-ajax-linkpager-widget to replace the CLinkPager control. When the user clicks on the paging link, use Ajax to update the data:

<?php $this->renderPartial('_userlist', array('users' => $users)); ?>

<?php $this->widget('ext.yii-ajax-linkpager-widget.EAjaxLinkPager', array(
    'ajaxUpdate' => 'userlist',
    'pages' => $pagination,
)); ?>

In the _controller folder, we need to add a method actionPage, in which paging requests are processed:

public function actionPage()
{

// 处理分页请求，返回分页数据
$pagination = new CPagination(10000);
$pagination->pageSize = 20;
$pagination->setCurrentPage($_GET['page']);

$users = User::model()->findAll(array(
    'limit' => $pagination->getLimit(),
    'offset' => $pagination->getOffset(),
));

$this->renderPartial('_userlist', array('users' => $users));

}

2.2 Caching paging data

Caching paging data to the cache server can greatly improve the performance of paging. When the user requests paging data, first check whether the cache server has cached data, and if so, return the data directly; otherwise, query the database, store the data in the cache server, and then return the data.

We can use the caching mechanism provided by the Yii framework. Use COutputCache in the controller's actionIndex method to cache paging data:

public function actionIndex()
{

// 缓存时间为10分钟
$cacheId = __CLASS__.__METHOD__.md5(Yii::app()->user->id);
$cacheTime = 10*60;

if(!$this->beginCache($cacheId, array(
    'duration' => $cacheTime,
)))
{
    $pagination = new CPagination(10000);
    // ...
    $users = User::model()->findAll(array(
        'limit' => $pagination->getLimit(),
        'offset' => $pagination->getOffset(),
    ));

    $this->render('index', array(
        'users' => $users,
        'pagination' => $pagination,
    ));

    $this->endCache();
}

}

When the user requests paging data, If cache data exists in the cache server, the cache data is returned directly; otherwise, the database is queried, the data is stored in the cache server, and the data is returned.

To sum up, the data paging function in the Yii framework is easy to implement and supports a variety of optimization methods, which can greatly improve the user experience of web applications. Whether it is a small amount of data or a large amount of data, data paging can be easily implemented.

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