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Implementation of dynamically extracting data from database in PHP entry page_PHP tutorial
Implementation of dynamically extracting data from database in PHP entry page_PHP tutorial
Summary: When using PHP to create a dynamic web page, before submitting it to the server, let PHP immediately retrieve the values of other related fields from the database based on the value of a field entered by the user on the current page and display it on the current page. This is a PHP program. Difficulties in development. This article uses a specific example to introduce in detail how to cleverly combine the two HTML embedded languages php and javascript to solve this difficulty.
Keywords: php, dynamic, html.
Nowadays websites have developed from providing static information to interactive ways of providing dynamic information services. The form of web information services can be summarized in two points: providing information to customers; and recording information submitted by customers. To provide these two services, the problems that need to be solved are: how to quickly allow users to quickly extract the information they want from the large amount of information on their own websites, and how to effectively record the information submitted by users to facilitate future user searches. These problems can be solved by adding database support to the website.
Because PHP can provide good support for a variety of databases, and the PHP script is directly embedded in the HTML document, it is very convenient to use. Therefore, PHP is one of the most popular server-side embedded languages on the Internet. In addition, compared with other server-side scripting languages such as ASP, PHP is free and open source and provides cross-platform support, which allows it to easily adapt to various heterogeneous network environments in today's networks; it allows web page producers to quickly , easily create powerful dynamic web pages. However, since PHP is embedded on the server side, a more intuitive understanding is that the PHP statement is executed on the server, so it only receives and processes the content on the current page when it is submitted. And when the content you need is dynamically extracted from the library based on the value of a field entered on the customer's current page, PHP is powerless. For example: you want to provide customers with an "Ordering Contract" entry page, which contains some "Supplier Information" entries, and the detailed information of each supplier has been entered in a "Merchant" dictionary table in advance. Now it is required that the current When a customer selects a "supplier" on the current page, some of the supplier's information such as "account opening bank, account number, address, phone number, etc." are immediately extracted from the "merchant" dictionary and displayed on the current page. For customers to use directly or modify. Such a requirement is easy to implement using visual programming languages such as pb and vb, but pb and vb are not suitable for writing dynamic web pages; php is suitable for writing dynamic web pages, but due to server-side embedding, submission cannot be obtained in time The variable value on the previous page, so it is difficult to achieve the above requirements. During the programming process, I cleverly combined PHP with JavaScript to solve this difficulty.
We know that it is also an embedded statement, but javascript is different from php language. Because PHP is server-side embedding, and JavaScript is client-side embedding, both JavaScript statements are executed on the client's browser, which determines that JavaScript can obtain the variable values on the current page in time, but it cannot directly operate the server-side database. . Therefore, combining the two to create powerful dynamic web pages is a perfect match. For the convenience of description, the following only takes the address of the selected supplier from the dictionary table as an example to illustrate the specific method. When multiple fields need to be taken out, the method is similar, but when using the javascript function to take out one by one from the string, you need to be more careful.
1． Write a php function
The function of this function is to take out all qualified "supplier information" from the "merchant" dictionary table and store it in a string variable $khsz.
function khqk_tq($questr){
global $dbconn;
$dbq_resl=sybase_query($questr,$dbconn); //Send a query string for sybase to execute .
$dbq_rows=sybase_num_rows($dbq_resl); //Get the number of rows returned.
$j=0;
for ($i=0;$i<$dbq_rows;$i++){ //Create a loop to take out the required fields from each row and put into the array $k[].
$k[]=sybase_result($dbq_resl,$i,"kh_id"); //Get the supplier number selected by the user.
$add=sybase_result($dbq_resl,$i,"address"); //Get the supplier address.
if ($add==""):
$k[]="None";
else :
$k[]= sybase_result($dbq_resl,$i,"address");
endif;
$khsz=$khsz.$k[$j]."|".$k[$j+ 1]."|"; //Connect each field value to the variable $khsz with "|" as the delimiter to form a long string.
$j=$j+2;
}
return $khsz;
}
2. Write a javascript function
The function of this function is to find the address of the supplier based on the kh_id value from the string and embed it into the html file.
3. Combine the two in html and use each other
$khinfo="select kh_id,address from kh where co_id=$s_coid and type='g' order by kh_id";
//Put the sql statement to obtain supplier information into the variable $khinfo.
$k=khqk_tq($khinfo); //Call the php function and put the returned string value into the variable $k.