Detailed explanation of how thinkphp implements paging function

ThinkPHP is a powerful PHP development framework that provides many convenient functions and tools for developers. One of the more important functions is paging. Pagination is an important part of website development. It allows users to browse website content more conveniently and allows developers to better manage and display data. How is paging implemented in ThinkPHP? This article will introduce it to you in detail.

1. Principle of paging

Before introducing ThinkPHP’s paging function, let’s first understand the basic principles of paging.

The content on the website is rich and colorful, but for content with a large amount of data, if it is placed on one page, the page will load slowly, affecting the user experience, and it will also increase the difficulty of data management. Therefore, paging has become a common method to solve this problem.

The principle of paging is to divide the data into several pages according to how many items are displayed on one page, and each page displays a fixed amount of data. Paging is usually divided into two methods: one is SQL-based paging, and the other is array-based paging.

2. SQL-based paging

In ThinkPHP, paging is implemented based on SQL statements. We can use the limit method provided by ThinkPHP to implement paging queries. The following is a simple example:

//获取分页数据，每页显示10条数据
$users = Db::name('user')->order('id desc')->limit(10)->select();

In the above code, Db::name('user') represents querying the data of the user table, order The ('id desc') statement means to sort in descending order according to the id field, and limit(10) means to display 10 pieces of data per page.

Next, we also need to add a paging navigation bar to the template page. In ThinkPHP, we can use the paginate method to generate a pagination navigation bar, as shown in the following example:

//每页显示10条数据
$users = Db::name('user')->paginate(10);
//将分页数据赋值到模板中
$this->assign('users', $users);
//在模板中输出分页数据
{{$users|raw}}

In the above code, paginate(10) represents each page Display 10 pieces of data, the $this->assign method is used to assign paging data to the template, and the {{$users|raw}} code is used to output paging data. In this way, we can display the paging navigation bar on the page.

3. Array-based paging

In addition to SQL-based paging, ThinkPHP also provides array-based paging. In most cases, array-based paging is more flexible than SQL-based paging.

In ThinkPHP, we can use the array_slice function to implement array-based paging, as shown in the following example:

//数据总数
$count = count($data);
//每页显示10条数据
$pagesize = 10;
//当前页
$page = input('page', 1);
//计算总页数
$pagecount = ceil($count / $pagesize);
//起始位置
$start = ($page - 1) * $pagesize;
//获取当前页的数据
$list = array_slice($data, $start, $pagesize);
//将分页数据赋值到模板中
$this->assign('list', $list);
//在模板中输出分页数据
{{$list|raw}}

In the above code, count($ data) represents the total number of data, $pagesize represents the amount of data displayed on each page, input('page', 1) represents getting the current page number, if not obtained The default is the first page, ceil($count / $pagesize) represents the total number of pages, ($page - 1) * $pagesize represents the starting position, and finally uses The array_slice function obtains the data of the current page. Then assign the paging data to the template and use {{$list|raw}} to output the paging data.

4. Summary

Pagination is a very important part of website development. It allows users to browse the content of the website more conveniently, and also facilitates data management for developers. In ThinkPHP, we can use SQL-based paging and array-based paging to implement paging. Either way, once you master the basic principles, it will be easier to operate in practice. At the same time, mastering paging skills is also an important step in becoming a good developer.

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