<?php class DB { const HOST='127.0.0.1'; const USER='root'; const PASS='root'; const DATA='mooc'; static public $_instance; private function __construct() { mysql_connect(DB::HOST,DB::USER,DB::PASS); mysql_set_charset('utf8'); mysql_select_db(DB::DATA); } public static function getInstance() { if(!self::$_instance instanceof self) { self::$_instance=new self; } return self::$_instance; } } $model=DB::getInstance(); //连接数据库,并且测试 $sql="select * from user"; $res=mysql_query($sql); while($row=mysql_fetch_assoc($res)) { var_dump($row); } ?>
The above is the detailed content of PHP universal database connection method. For more information, please follow other related articles on the PHP Chinese website!

PHPidentifiesauser'ssessionusingsessioncookiesandsessionIDs.1)Whensession_start()iscalled,PHPgeneratesauniquesessionIDstoredinacookienamedPHPSESSIDontheuser'sbrowser.2)ThisIDallowsPHPtoretrievesessiondatafromtheserver.

The security of PHP sessions can be achieved through the following measures: 1. Use session_regenerate_id() to regenerate the session ID when the user logs in or is an important operation. 2. Encrypt the transmission session ID through the HTTPS protocol. 3. Use session_save_path() to specify the secure directory to store session data and set permissions correctly.

PHPsessionfilesarestoredinthedirectoryspecifiedbysession.save_path,typically/tmponUnix-likesystemsorC:\Windows\TemponWindows.Tocustomizethis:1)Usesession_save_path()tosetacustomdirectory,ensuringit'swritable;2)Verifythecustomdirectoryexistsandiswrita

ToretrievedatafromaPHPsession,startthesessionwithsession_start()andaccessvariablesinthe$_SESSIONarray.Forexample:1)Startthesession:session_start().2)Retrievedata:$username=$_SESSION['username'];echo"Welcome,".$username;.Sessionsareserver-si

The steps to build an efficient shopping cart system using sessions include: 1) Understand the definition and function of the session. The session is a server-side storage mechanism used to maintain user status across requests; 2) Implement basic session management, such as adding products to the shopping cart; 3) Expand to advanced usage, supporting product quantity management and deletion; 4) Optimize performance and security, by persisting session data and using secure session identifiers.

The article explains how to create, implement, and use interfaces in PHP, focusing on their benefits for code organization and maintainability.

The article discusses the differences between crypt() and password_hash() in PHP for password hashing, focusing on their implementation, security, and suitability for modern web applications.

Article discusses preventing Cross-Site Scripting (XSS) in PHP through input validation, output encoding, and using tools like OWASP ESAPI and HTML Purifier.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Zend Studio 13.0.1
Powerful PHP integrated development environment

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

WebStorm Mac version
Useful JavaScript development tools

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft
