What are the database migration and merging tips for learning MySQL?

What are the database migration and merging techniques for learning MySQL?

As a commonly used database management system, MySQL is often used in software development and data management. As business develops and needs change, databases sometimes need to be migrated and merged. This article will introduce several common MySQL database migration and merging techniques and provide corresponding code examples.

1. Database migration

1.1 Use the mysqldump tool to export the database

mysqldump is MySQL’s own tool for exporting the database. The entire database or a specified table can be exported to a .sql file through mysqldump, and then imported through the mysql tool on another server.

The sample code is as follows:

# 导出整个数据库
mysqldump -u用户名 -p密码 数据库名 > 导出的文件路径

# 导出指定表
mysqldump -u用户名 -p密码 数据库名 表名 > 导出的文件路径

1.2 Use MySQL Replication to implement database migration

MySQL Replication is a data replication mechanism provided by MySQL, which can replicate the data of a database in real time into another database. By configuring the relationship between the master and slave servers, write operations can be performed on the master database, and the slave database will automatically synchronize data.

The sample code is as follows:

First, configure on the master database:

# 开启二进制日志
vi /etc/my.cnf
在[mysqld]段中添加：log-bin=mysql-bin
重启MySQL服务：service mysql restart

# 创建一个用于复制的账户
GRANT REPLICATION SLAVE ON *.* TO 'slave_user'@'从服务器IP' IDENTIFIED BY '密码';

Then, configure on the slave database:

# 配置主从关系
CHANGE MASTER TO MASTER_HOST='主服务器IP', MASTER_USER='slave_user', MASTER_PASSWORD='密码', MASTER_LOG_FILE='主服务器上的二进制日志文件名', MASTER_LOG_POS=主服务器上的二进制日志位置;
# 启动复制过程
START SLAVE;

1.3 Use MySQL data import and export commands

In addition to using the mysqldump tool to export the database, MySQL also provides other data import and export commands, such as SELECT INTO OUTFILE and LOAD DATA INFILE.

The sample code is as follows:

Export the query results to a file:

SELECT * INTO OUTFILE '导出的文件路径' FROM 数据库名.表名;

Import the file data into the table:

LOAD DATA INFILE '导入的文件路径' INTO TABLE 数据库名.表名;

2. Database merge

2.1 Use the INSERT INTO statement

If you merge multiple databases into one database, you can use the INSERT INTO statement to insert data into the table of the target database.

The sample code is as follows:

INSERT INTO 目标数据库名.目标表名 SELECT * FROM 源数据库名.源表名;

2.2 Using the UNION statement

If you merge data from multiple databases into one query result, you can use the UNION statement.

The sample code is as follows:

SELECT 列名 FROM 数据库名.表名1
UNION
SELECT 列名 FROM 数据库名.表名2;

2.3 Use external tools for data merging

In addition to using MySQL’s own statements for data merging, you can also use external tools, such as DataGrip , Navicat, etc. for data merging operations.

To sum up, there are many ways to learn MySQL database migration and merging skills. This article describes several common techniques and provides corresponding code examples. Based on actual needs, you can choose a suitable method for database migration and merge operations. I hope this article will be helpful for learning MySQL database migration and merging skills.

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