php5 upgrade php7 fails to connect to mysql database
Reason:
php5 uses the mysql_connect function to connect to the Mysql database, but you will find that this method does not work on php7 It works. The reason is very simple. php7 has abandoned this function. Now php7 probably uses two methods to connect to the MySQL database.
Method 1:
Use function connection. The original mysql_connect() is changed to the mysqli_connect() function. If you add this letter, everything will be normal.
Syntax:
变量名 = mysqli_connect(主机地址，用户名，密码，数据库名);
Method 2:
Use object-oriented method.
Grammar:
变量名 = new mysqli(主机地址，用户名，密码，数据库名)；
Recommended tutorial: PHP7 tutorial
The above is the detailed content of php5 upgrade php7 fails to connect to mysql database. 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
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
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
1653
14
1413
52
1304
25
1251
29
1224
24
MySQL's Role: Databases in Web Applications
Apr 17, 2025 am 12:23 AM
The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.
How to start mysql by docker
Apr 15, 2025 pm 12:09 PM
The process of starting MySQL in Docker consists of the following steps: Pull the MySQL image to create and start the container, set the root user password, and map the port verification connection Create the database and the user grants all permissions to the database
Laravel Introduction Example
Apr 18, 2025 pm 12:45 PM
Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests.
Solve database connection problem: a practical case of using minii/db library
Apr 18, 2025 am 07:09 AM
I encountered a tricky problem when developing a small application: the need to quickly integrate a lightweight database operation library. After trying multiple libraries, I found that they either have too much functionality or are not very compatible. Eventually, I found minii/db, a simplified version based on Yii2 that solved my problem perfectly.
Laravel framework installation method
Apr 18, 2025 pm 12:54 PM
Article summary: This article provides detailed step-by-step instructions to guide readers on how to easily install the Laravel framework. Laravel is a powerful PHP framework that speeds up the development process of web applications. This tutorial covers the installation process from system requirements to configuring databases and setting up routing. By following these steps, readers can quickly and efficiently lay a solid foundation for their Laravel project.
How to install mysql in centos7
Apr 14, 2025 pm 08:30 PM
The key to installing MySQL elegantly is to add the official MySQL repository. The specific steps are as follows: Download the MySQL official GPG key to prevent phishing attacks. Add MySQL repository file: rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm Update yum repository cache: yum update installation MySQL: yum install mysql-server startup MySQL service: systemctl start mysqld set up booting
MySQL and phpMyAdmin: Core Features and Functions
Apr 22, 2025 am 12:12 AM
MySQL and phpMyAdmin are powerful database management tools. 1) MySQL is used to create databases and tables, and to execute DML and SQL queries. 2) phpMyAdmin provides an intuitive interface for database management, table structure management, data operations and user permission management.
Centos install mysql
Apr 14, 2025 pm 08:09 PM
Installing MySQL on CentOS involves the following steps: Adding the appropriate MySQL yum source. Execute the yum install mysql-server command to install the MySQL server. Use the mysql_secure_installation command to make security settings, such as setting the root user password. Customize the MySQL configuration file as needed. Tune MySQL parameters and optimize databases for performance.
