Introduction to the simple paging function of developing a simple news release system with PHP

Paging display is a very common method of browsing and displaying large amounts of data, and is one of the most commonly processed events in web programming.

The so-called paging display means that the result set in the database is artificially divided into sections for display. Two initial parameters are required here:

The number of news displayed on each page: $limitNews

Get the current number of pages: $page

Because the computer language defaults to starting from 0 to obtain records

If the number displayed per page is set to 3, $limitNews = 3,

Then the first page $page = 1 will display three records of 0, 1, 2

The second page $page = 2 will display three records of 3, 4, and 5

The third page $page = 3 will display three records of 6, 7, and 8

and so on. . . . . . . . .

Set a parameter $limitFrom from which piece of data to start reading

You can get it from the above rules:

$limitFrom = ($page - 1 ) * $limitNews;

will obtain data starting from the 0th, 3rd, and 6th items respectively.

Next we need to connect to the database and read the data

We still use the database name test and table name new:# created earlier ##

<?php
$link = mysqli_connect('localhost','uesrname','password','test');

$sql = "select * from new";  //  select * from表示獲取全部字段的值

$sqlCount = "select count(*) from new";    //count(*)統(tǒng)計的是結(jié)果集的總條數(shù)
?>

Get the

total number of news in the database table through query statements$countNews

<?php
$retQuery = mysqli_query($link, $sqlCount);  //查詢數(shù)量sql語句

$retCount = mysqli_fetch_array($retQuery);   //獲取數(shù)量

$count = $retCount[0]?$retCount[0]:0;   //判斷獲取的新聞數(shù)量

$countNews = $count;
?>

Another parameter needs to be given here

$countPage How many pages are displayed in total

Now another problem arises. If there are 10 news records and 3 records are displayed on each page, then What to do with the remaining one?

We need to use % remainder to make the judgment:

<?php
$countPage = $countNews%$limitNews;   //求余數(shù)獲取分頁數(shù)量能否被除盡

if(($countPage) > 0) {  //獲取的頁數(shù)有余
  $countPage = ceil($countNews/$limitNews);  
  
// ceil() 函數(shù)向上舍入為最接近的整數(shù),除不盡則取整數(shù)+1頁, 10個新聞每個頁面顯示3個，成3個頁面，剩余1個單獨成1個頁面，這樣總共有4個頁面
} else {
  $countPage = $countNews/$limitNews;  //如果是9個新聞每個頁面顯示3個，成3個頁面
}
?>

Other parameters

Previous page$prev, next page$next；

In the paging function, there are often clicks on "previous page" and "next page" to jump

Let me first talk about the idea of ????implementing the PHP code function:

The previous page $prev is the current page $page -1. Jump to the previous page step by step. When the current page $page is the first page, jump forward to page 0. This will obviously cause bugs.

Here we need to give it a setting. When the current page $page is the first page, click "Previous Page" to set it to be displayed as the first page. If not Jumped forward.

$prev = ($page - 1 <= 0 )?1:$page-1;

The next page$next is the current Page $page -1 jumps to the next page step by step. The problem is that when $page is the last page, click "Next Page" to jump back.

is similar to the previous page. We set Set it to display the last page.

$next = ($page + 1 > $countPage)?$countPage:$page+1;

//The current page number must be greater than When the total number of pages is displayed, the current page is displayed.

The page code is shown below:

<!DOCTYPE html>
<html>
<head>  
<meta charset=utf8">  
<title>分表頁</title>
</head>
<body>
   <div>
         <a href="?page=<?php echo $prev;?>">|上一頁</a>         
         <?php for($i=1; $i<=$countPage; $i++):?>         
         <a href="?page=<?php echo $i;?>"><?php echo $i;?></a>         
         <?php endfor;?>         
         <a href="?page=<?php echo $next;?>">|下一頁</a>
   </div>
</body>
</html>

Note: The above code uses a for loop to implement 1,2,3. . . . page effect.

Continuing Learning

new file

<?php $link = mysqli_connect('localhost','usermane','password','test'); mysqli_set_charset($link, "utf8"); if (!$link) { die("連接失敗:".mysqli_connect_error()); } $page = isset($_GET['page'])?$_GET['page']:1;//獲取當(dāng)前分頁數(shù) $limitNews = 3; //每頁顯示新聞數(shù)量 $countNews = 0; //總共有多少條新聞 $countPage = 0; //一共有多少頁數(shù) $limitFrom = ($page - 1) * $limitNews;//從第幾條數(shù)據(jù)開始讀記錄 //每頁顯示3個 //page = l limit 0 //page = 2 limit 3 //page = 3 limit 6 $sql = "select * from new"; $sqlCount = "select count(*) from new"; $retQuery = mysqli_query($link, $sqlCount); //查詢數(shù)量sql語句 $retCount = mysqli_fetch_array($retQuery); //獲取數(shù)量 $count = $retCount[0]?$retCount[0]:0; //判斷獲取的新聞數(shù)量 $countNews = $count; $countPage = $countNews%$limitNews; //求余數(shù)獲取分頁數(shù)量能否被除盡 if(($countPage) > 0) { //獲取的頁數(shù)有余 $countPage = ceil($countNews/$limitNews); // ceil() 函數(shù)向上舍入為最接近的整數(shù),除不盡則取整數(shù)+1頁, 10個新聞每個頁面顯示3個，成3個頁面，剩余1個成1個頁面 } else { $countPage = $countNews/$limitNews; } $prev = ($page - 1 <= 0 )?1:$page-1; //上一頁 $next = ($page + 1 > $countPage)?$countPage:$page+1; //下一頁 $result = mysqli_query($link, $sql); ?> <!DOCTYPE html> <html> <head> <meta charset=utf8"> <title>分頁</title> </head> <body> <div> <a href="?page=<?php echo $prev;?>">|上一頁</a> <?php for($i=1; $i<=$countPage; $i++):?> <a href="?page=<?php echo $i;?>"><?php echo $i;?></a> <?php endfor;?> <a href="?page=<?php echo $next;?>">|下一頁</a> </div> </body> </html>

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