


How to implement the addition, deletion, check and modification function of the database in php
With the development of the Internet, Web technology is also constantly improving, and PHP, as a mature and powerful Web programming language, has become one of the main choices for Web development. In PHP development, addition, deletion, search, and modification are the most basic operations. This article will describe how to implement these operations.
1. Add data
Adding data is one of the most common operations in web development. In PHP, we usually use MySQL database to store data. Below is a sample code for adding a new user to a MySQL database.
<?php $servername = "localhost"; $username = "username"; $password = "password"; $dbname = "myDB"; // 创建连接 $conn = new mysqli($servername, $username, $password, $dbname); // 检测连接是否成功 if ($conn->connect_error) { die("连接失败: " . $conn->connect_error); } // 插入新用户 $sql = "INSERT INTO users (username, password, email) VALUES ('John', 'Doe', 'john@example.com')"; if ($conn->query($sql) === TRUE) { echo "新记录插入成功"; } else { echo "Error: " . $sql . "<br>" . $conn->error; } // 关闭连接 $conn->close(); ?>
In the above example, we use the mysqli_connect() function to connect to the MySQL database and use the INSERT INTO statement to add a new user to the users table. If the insertion operation is successful, the page will output "New record inserted successfully".
2. Deleting data
Deleting data is another common operation in web development. In PHP, we can use the DELETE statement to delete one or more pieces of data from the MySQL database. Below is a sample code to delete a user named "John".
<?php $servername = "localhost"; $username = "username"; $password = "password"; $dbname = "myDB"; // 创建连接 $conn = new mysqli($servername, $username, $password, $dbname); // 检测连接是否成功 if ($conn->connect_error) { die("连接失败: " . $conn->connect_error); } // 删除名为“John”的用户 $sql = "DELETE FROM users WHERE username='John'"; if ($conn->query($sql) === TRUE) { echo "记录删除成功"; } else { echo "Error deleting record: " . $conn->error; } // 关闭连接 $conn->close(); ?>
In the above example, we use the DELETE FROM statement to delete the user named "John". If the deletion is successful, the page will output "Record Deletion Successful".
3. Querying data
Querying data is one of the most common operations in web development. In PHP, we can use the SELECT statement to query data from the MySQL database. Below is a sample code to query the usernames of all users.
<?php $servername = "localhost"; $username = "username"; $password = "password"; $dbname = "myDB"; // 创建连接 $conn = new mysqli($servername, $username, $password, $dbname); // 检测连接是否成功 if ($conn->connect_error) { die("连接失败: " . $conn->connect_error); } // 查询所有用户的用户名 $sql = "SELECT username FROM users"; $result = $conn->query($sql); if ($result->num_rows > 0) { // 输出数据 while($row = $result->fetch_assoc()) { echo "username: " . $row["username"]. "<br>"; } } else { echo "0 结果"; } // 关闭连接 $conn->close(); ?>
In the above example, we use the SELECT statement to query the usernames of all users. If the query is successful, the page will output the username of each user.
4. Update data
Updating data is another important operation in web development. In PHP, we can update data in the MySQL database using the UPDATE statement. Below is a sample code that updates the email of a user named "John".
<?php $servername = "localhost"; $username = "username"; $password = "password"; $dbname = "myDB"; // 创建连接 $conn = new mysqli($servername, $username, $password, $dbname); // 检测连接是否成功 if ($conn->connect_error) { die("连接失败: " . $conn->connect_error); } // 更新名为“John”的用户的电子邮件 $sql = "UPDATE users SET email='john@example.com' WHERE username='John'"; if ($conn->query($sql) === TRUE) { echo "记录更新成功"; } else { echo "Error updating record: " . $conn->error; } // 关闭连接 $conn->close(); ?>
In the above example, we use the UPDATE statement to update the email of a user named "John". If the update is successful, the page will output "Record updated successfully".
Summary
Through the introduction of this article, we have learned how to implement basic add, delete, search, and modify operations in PHP. These operations are one of the most common operations in web development, and they are also the basic knowledge that we must master when learning PHP programming.
The above is the detailed content of How to implement the addition, deletion, check and modification function of the database in php. For more information, please follow other related articles on the PHP Chinese website!

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

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

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics



PHP 8's JIT compilation enhances performance by compiling frequently executed code into machine code, benefiting applications with heavy computations and reducing execution times.

The article discusses OWASP Top 10 vulnerabilities in PHP and mitigation strategies. Key issues include injection, broken authentication, and XSS, with recommended tools for monitoring and securing PHP applications.

The article discusses securing PHP file uploads to prevent vulnerabilities like code injection. It focuses on file type validation, secure storage, and error handling to enhance application security.

The article discusses symmetric and asymmetric encryption in PHP, comparing their suitability, performance, and security differences. Symmetric encryption is faster and suited for bulk data, while asymmetric is used for secure key exchange.

The article discusses implementing robust authentication and authorization in PHP to prevent unauthorized access, detailing best practices and recommending security-enhancing tools.

Article discusses retrieving data from databases using PHP, covering steps, security measures, optimization techniques, and common errors with solutions.Character count: 159

The article discusses strategies to prevent CSRF attacks in PHP, including using CSRF tokens, Same-Site cookies, and proper session management.

The article discusses the mysqli_query() and mysqli_fetch_assoc() functions in PHP for MySQL database interactions. It explains their roles, differences, and provides a practical example of their use. The main argument focuses on the benefits of usin
