PHP Example Tutorial: Implementing Dynamic Flip Function_PHP Tutorial

　Bkjia.Com PHP TutorialUsing php+mysql to display all database information on a web page is very simple and interesting. When there is very little database information, the page display It is still satisfactory, but when there is a lot of data in the database, the display of the page will become very bad. Let's introduce how to display the number of data on the current page and how to implement the dynamic flip function.

This article will introduce the implementation of two page turning display functions:

First introduce the database syntax used in page turning:

mysql_query("select * from table order by id desc");

This database statement is all too familiar. It is used to search for records and display them in reverse order, but it does not work in the page turning function. The following expanded syntax is the core function of realizing page turning:

mysql_query("select * from table order by id desc limit $start,$limit");

mysql_query("select * from table order by id desc limit $start,$limit");

Here $start is the starting row of the database search, $limit is the search starting from the starting row and ending with $limit records. Well, with this core function, we can start the page turning function;

The first page turning function. The function introduced here is the simplest one among the page turning functions. It can only realize page turning forward and page backward. The special news and download center of this site can only turn pages forward. This is the page function. First introduce the idea of ​​​​implementing the page turning function. First determine the number of data records fixedly displayed on the current page. Assume it is 20 records. Set the value of $limit to 20: $limit=20;

When displaying database records, they must start from the first one, so the initial value of $start is set here to 0:$start=0;

The realization of the page turning function relies on the dynamic change of $start. When turning the page backward, $start regularly adds $limit: $start+$limit; while when turning the page forward, $start regularly subtracts $. limit:$start-$limit;

With the above ideas in mind, you can start designing the program page.php:

以下为引用的内容：

//设置当前页显示的数量(这个数量可任意设置)
$limit=20;

//初始化数据库搜索起始记录
if (!empty($start)) $start=0;

mysql_connect("localhost","","");
mysql_select_db(database);

//设置数据库记录总数
$result=mysql_query("select * from table");
$num_max=mysql_numrows($result);

$result=mysql_query("select * from table order by id desc limit $start,$limit);
$num=mysql_numrows($result);

echo "

";

if (!empty($num)) {
for ($i=0;$i<$num;$i++) {
$val=mysql_result($result,$i,"val");
$val1=mysql_result($result,$i,"val1");
echo "

";
}
}

echo "

翻页功能
$val	$val1
"; //设置向前翻页的跳转 $prve=$start-$limit; if ($prve>=0) { echo "prve"; } //设置向后翻页的跳转 $next=$start+$limit; if ($next<$num_max) { echo "next"; } echo "

";
?>

The following is the quoted content: //Set the number displayed on the current page (this number can be set arbitrarily) <🎜>$limit=20;<🎜> <🎜>//Initialize database search start record <🎜>if (!empty($start)) $start=0;<🎜> <🎜>mysql_connect("localhost","",""); <🎜>mysql_select_db(database);<🎜> <🎜>//Set the total number of database records <🎜>$result=mysql_query("select * from table"); <🎜>$num_max=mysql_numrows($result);<🎜> <🎜>$result=mysql_query("select * from table order by id desc limit $start,$limit); <🎜>$num=mysql_numrows($result);<🎜> <🎜>echo ""; if (!empty($num)) { for ($i=0;$i<$num;$i++) { $val=mysql_result($result,$i,"val" ); $val1=mysql_result($result,$i,"val1"); echo ""; } } echo "

Page turning function
$val	$val1
"; //Set forward page jump$prve=$start-$limit; if ($prve>=0) { echo "prve"; } //Set the page forward jump$next=$start+$limit; if ($next<$num_max) { <🎜>echo "next"; } echo "

"; ?>

A program with forward and backward flip functions has been completed. However, this function will become very cumbersome when processing more data to display. The following will continue to introduce a more powerful and complex page turning function-loop Page turning (I always call it this because I can’t find a more appropriate name).:)

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