How to migrate mysql database

MySQL database migration refers to the process of migrating data and structures in one database to another database. In actual projects, you may encounter situations where you need to migrate the database to a new server, upgrade the database version, merge multiple databases, etc. The following will introduce how to migrate MySQL database and provide specific code examples.

1. Export the original database
   First, use the export tool on the server where the original database is located to export the data and structure into a SQL file. Commonly used export tools include the mysqldump command and phpMyAdmin. The following is a sample code exported using the mysqldump command:

mysqldump -u 用户名 -p 密码 数据库名 > 数据库名.sql

2. Import to the target database
   Next, use the import tool on the server where the target database is located to import the previously exported SQL file. . The following is a sample code imported using the mysql command:

mysql -u 用户名 -p 密码 目标数据库名 < 数据库名.sql

3. Modify the configuration file
   After the database migration is completed, the corresponding database connection configuration needs to be modified in the project. Find the configuration file in the project (such as config.php) and modify the following parameters to the connection information of the target database:

$host = "目标数据库的主机名";
$username = "目标数据库的用户名";
$password = "目标数据库的密码";
$database = "目标数据库名";
$conn = new mysqli($host, $username, $password, $database);

Note: Depending on the actual project situation, sometimes it is necessary to modify the character set and port of the database and other parameters.

4. Test connection
   In order to ensure that the database connection is normal, you can add test connection code to the project. The following is a simple sample code:

$conn = new mysqli($host, $username, $password, $database);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully!";

By running the above code, if "Connected successfully!" is displayed in the browser, it means the connection is normal.

In summary, the above are the steps for MySQL database migration and related code examples. When performing actual database migration, these steps and codes can be flexibly used according to the specific situation, or combined with other tools and methods for migration.

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