Using the MySQL Shell for administration and scripting
Jul 13, 2025 am 02:43 AM
The method of connecting to the database by MySQL Shell is to use the mysqlsh command to start and enter connection information, or directly specify user@host:port on the command line; 1. The startup method is flexible, supports interactive input or directly specifying parameters; 2. Pay attention to SSL settings and authentication methods, especially when remote connections, to ensure correct permissions and passwords; 3. After entering the shell, the default is SQL mode, which can perform regular SQL operations; 4. Support switching to JS or Python mode to write complex scripts to achieve automated tasks; 5. Script writing requires attention to mode selection, output format, exception handling and file saving; 6. Provide practical tips, such as viewing the current mode, switching paths, multi-instance connections, and consulting help documents, which help solve common problems.
MySQL Shell is a powerful tool that can not only be used to manage databases, but also write scripts to automate operations. If you have used traditional MySQL client before, you may think it is a bit different, but it is actually more flexible to use.
How to connect to the database?
The first step with MySQL Shell is to connect to the database instance. You can start with the mysqlsh command and enter the connection information. You can also specify it directly on the command line:
mysqlsh user@host:port
Remember to confirm whether SSL is used and whether the authentication method is correct when connecting, especially when connecting to a remote server. If the password is incorrect or the permissions are insufficient, the Shell will prompt an error. At this time, you need to check the user permissions and access control settings.
Common commands for managing databases
After entering the shell, the default is SQL mode, and you can execute SQL statements like you normally do. For example, check the current database, user, table structure, etc.:
\sql USE mydb; SHOW TABLES; DESCRIBE mytable;
However, MySQL Shell also supports JavaScript and Python modes, which are suitable for batch operations or scripting. For example, switch to JS mode:
\js
Then you can write some simple logic, such as traversing all databases:
session.runSql("SHOW DATABASES;");
var result = session.fetchAll();
result.forEach(function(row) { print(row[0]); });This way you can write scripts in the shell for tasks such as data collection, status checking, etc.
Script writing tips and precautions
If you plan to write automation scripts using MySQL Shell, there are a few things to note:
- Pattern selection : JS and Python patterns are more suitable for writing scripts with complex logic, while SQL patterns are suitable for simple queries.
- Output format : The default output is in table form. It is recommended to change it to JSON or silent mode in the script to facilitate subsequent processing.
- Exception handling : The script will not automatically exit when an error occurs when it runs. It is best to add try-catch or judge the return value.
- Save script files : You can save common scripts as
.jsor.pyfiles and load and execute them with thesourcecommand.
For example, you can write a script to check the master-slave copy status:
try {
var res = dba.getReplicaSet().status();
print("Replication status:", res.ok);
} catch (e) {
print("Error checking replication:", e);
}Such scripts can be run regularly and used together with the monitoring system.
Tips and FAQs
Sometimes you will encounter some strange problems, such as the shell prompts "Session not active" or "Command not found", which is usually because the pattern is not correct or the syntax is incorrect. A few tips to remember:
- You can use
\statusto view the current mode - Switch mode with
\sql,\jsor\py - Pay attention to the difference between relative and absolute paths for script path issues
- When connecting multiple instances, use
\\connectto switch context
In addition, the Shell help document is actually quite complete. Enter \help or function name and add .help() to quickly check the usage.
Basically all this is it. MySQL Shell has many functions, but after mastering the basic operations, you will find that it is much better than traditional clients.
The above is the detailed content of Using the MySQL Shell for administration and scripting. For more information, please follow other related articles on the PHP Chinese website!
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