You will encounter many problems in caching. This article will compare SESSION and COOKIE.
[Cookie]
1. Definition->Exists in the browser, even if the browser is closed or the connection is interrupted, the user can still maintain the data status;
2. Life cycle -> By default, during the browser session (data is saved in memory), the validity period is set, and the data is saved on the hard disk;
3. Effective path -> The effective path path needs to be set, the default path Is the current path. If all paths need to be set to '/';
4. Valid domain name->Set the domain name domain, indicating that the path under the domain name is valid, and the default is the current path of the current domain name;
5. Cookie deletion-> Directly use setcookie("name",time()-1);
6. When does the cookie take effect-> After the setcookie() function, the client will be notified The client sends a cookie value. If it does not refresh or browse the next page, the client will not return the cookie;
7. Number of cookies -> A browser supports up to 30 cookies, and each The capacity of cookies cannot exceed 4KB, and the number of cookies set for each website cannot exceed 20;
【Session】
1. How to use -> Initialize with session_start() before use , create or load a session_id;
2. Life cycle-> From the time the user accesses the page to the time the user disconnects from the website, a SESSION ID will be automatically generated to represent the current user's relationship with other users. User;
3. Transfer data-> When the connection is not disconnected, data can be transferred between different pages
4. In the PHP environment, the session data is stored-> Here It’s more complicated. I copied a paragraph directly. In layman’s terms, it means configuring the storage path according to the configuration file. According to the id command file name, single file storage or hierarchical storage is performed. The original words are as follows:
[plain] view plain copy
Where is the data of SESSION stored?
Of course it is on the server side, but it is not saved in memory, but in a file or database.
By default, the SESSION saving method set in PHP.ini is files (session.save_handler = files), that is, SESSION data is saved by reading and writing files, and the directory where SESSION files are saved is determined by session.save_path Specify that the file name is prefixed with sess_, followed by the SESSION ID, such as: sess_c72665af28a8b14c0fe11afe3b59b51b. The data in the file is the SESSION data after serialization.
If the number of visits is large, more SESSION files may be generated. In this case, you can set up a hierarchical directory to save SESSION files. The efficiency will be greatly improved. The setting method is: session.save_path="N;/save_path ", N is the number of hierarchical levels, save_path is the starting directory.
When writing SESSION data, PHP will obtain the client's SESSION_ID, and then use this SESSION ID to find the corresponding SESSION file in the specified SESSION file storage directory. If it does not exist, create it, and finally store the data. After serialization, write to file [3]. Reading SESSION data is a similar operation process. The read data needs to be deserialized and the corresponding SESSION variable is generated.
Notes:
1. There cannot be any output before using the session_start() function;
2. The session will not be deleted because the browser is closed. But the default expiration time of cookies with session IDs is session level. That is to say, if the user closes the browser, the session ID stored on the client will be lost, but the session data stored on the server will not be deleted immediately. From the client, that is, the browser, it seems that the session has been deleted (because we have lost the session ID and cannot find the original session data).
This article explains the difference between SESSION and COOKIE. For more related content, please pay attention to the php Chinese website.
Related recommendations:
Understand how to obtain the client IP in php
Detailed explanation of the use of Session in php
Introduction to the differences between die(), exit(), and return in php
The above is the detailed content of Comparative introduction to SESSION and COOKIE under PHP. For more information, please follow other related articles on the PHP Chinese website!

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.

PHP is not dead. 1) The PHP community actively solves performance and security issues, and PHP7.x improves performance. 2) PHP is suitable for modern web development and is widely used in large websites. 3) PHP is easy to learn and the server performs well, but the type system is not as strict as static languages. 4) PHP is still important in the fields of content management and e-commerce, and the ecosystem continues to evolve. 5) Optimize performance through OPcache and APC, and use OOP and design patterns to improve code quality.

PHP and Python have their own advantages and disadvantages, and the choice depends on the project requirements. 1) PHP is suitable for web development, easy to learn, rich community resources, but the syntax is not modern enough, and performance and security need to be paid attention to. 2) Python is suitable for data science and machine learning, with concise syntax and easy to learn, but there are bottlenecks in execution speed and memory management.

PHP is used to build dynamic websites, and its core functions include: 1. Generate dynamic content and generate web pages in real time by connecting with the database; 2. Process user interaction and form submissions, verify inputs and respond to operations; 3. Manage sessions and user authentication to provide a personalized experience; 4. Optimize performance and follow best practices to improve website efficiency and security.

PHP uses MySQLi and PDO extensions to interact in database operations and server-side logic processing, and processes server-side logic through functions such as session management. 1) Use MySQLi or PDO to connect to the database and execute SQL queries. 2) Handle HTTP requests and user status through session management and other functions. 3) Use transactions to ensure the atomicity of database operations. 4) Prevent SQL injection, use exception handling and closing connections for debugging. 5) Optimize performance through indexing and cache, write highly readable code and perform error handling.

Using preprocessing statements and PDO in PHP can effectively prevent SQL injection attacks. 1) Use PDO to connect to the database and set the error mode. 2) Create preprocessing statements through the prepare method and pass data using placeholders and execute methods. 3) Process query results and ensure the security and performance of the code.


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

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Dreamweaver Mac version
Visual web development tools

Notepad++7.3.1
Easy-to-use and free code editor