bitsCN.com
1、创建新用户:
create user mark@localhost identified by '123456';
2、删除用户:
drop user mark@localhost;
3、修改用户名:
rename user mark@localhost to mark1@localhost;
4、修改用户密码:
set password for mark@localhost = password('111111');
5、授予权限:
(1)授予表权限:select,insert,delete,update,references,create,alter,index,drop,all或者all privileges.
use mysql;
grant select on user to mark@localhost;
(2)授予数据库权 限:select,insert,delete,update,references,create,alter,index,drop,create temporary tables,create view,show view,create routine,alter routine,execute routine,lock tables,all或者all privileges.
grant select on mysql.* to mark@localhost;
(3)授予用户权限:create user,show databases
grant create user on *.* to mark@localhost;
grant create,alter,drop on *.* to mark@localhost;
6、权限的转移和限制
(1)grant语句最后加with grant option,表示该用户有把自己的权限授予其它用户的权利,而不管其它用户是否有该权限。
grant select on mysql.user to mark@localhost with grant option;
重新用mark登录数据库后,mark可以授予别的用户相同的权限。
(2)with子句也可以对一个用户授予实用限制。
max_queries_per_hour 1 每小时查询数据库次数为1。
max_connections_per_hour 1 每小时可以连接数据库次数。
max_updates_per_hour 1 每小时可以修改数据库次数
max_user_connections 1 同时连接mysql的最大用户数。
如:
grant select on mysql.user to mark@localhost with max_queries_per_hour 1;
7、回收权限。
revoke select on mysql.user from mark@localhost;
bitsCN.com
In database optimization, indexing strategies should be selected according to query requirements: 1. When the query involves multiple columns and the order of conditions is fixed, use composite indexes; 2. When the query involves multiple columns but the order of conditions is not fixed, use multiple single-column indexes. Composite indexes are suitable for optimizing multi-column queries, while single-column indexes are suitable for single-column queries.

To optimize MySQL slow query, slowquerylog and performance_schema need to be used: 1. Enable slowquerylog and set thresholds to record slow query; 2. Use performance_schema to analyze query execution details, find out performance bottlenecks and optimize.

MySQL and SQL are essential skills for developers. 1.MySQL is an open source relational database management system, and SQL is the standard language used to manage and operate databases. 2.MySQL supports multiple storage engines through efficient data storage and retrieval functions, and SQL completes complex data operations through simple statements. 3. Examples of usage include basic queries and advanced queries, such as filtering and sorting by condition. 4. Common errors include syntax errors and performance issues, which can be optimized by checking SQL statements and using EXPLAIN commands. 5. Performance optimization techniques include using indexes, avoiding full table scanning, optimizing JOIN operations and improving code readability.

MySQL asynchronous master-slave replication enables data synchronization through binlog, improving read performance and high availability. 1) The master server record changes to binlog; 2) The slave server reads binlog through I/O threads; 3) The server SQL thread applies binlog to synchronize data.

MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.

The installation and basic operations of MySQL include: 1. Download and install MySQL, set the root user password; 2. Use SQL commands to create databases and tables, such as CREATEDATABASE and CREATETABLE; 3. Execute CRUD operations, use INSERT, SELECT, UPDATE, DELETE commands; 4. Create indexes and stored procedures to optimize performance and implement complex logic. With these steps, you can build and manage MySQL databases from scratch.

InnoDBBufferPool improves the performance of MySQL databases by loading data and index pages into memory. 1) The data page is loaded into the BufferPool to reduce disk I/O. 2) Dirty pages are marked and refreshed to disk regularly. 3) LRU algorithm management data page elimination. 4) The read-out mechanism loads the possible data pages in advance.

MySQL is suitable for beginners because it is simple to install, powerful and easy to manage data. 1. Simple installation and configuration, suitable for a variety of operating systems. 2. Support basic operations such as creating databases and tables, inserting, querying, updating and deleting data. 3. Provide advanced functions such as JOIN operations and subqueries. 4. Performance can be improved through indexing, query optimization and table partitioning. 5. Support backup, recovery and security measures to ensure data security and consistency.


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

Dreamweaver Mac version
Visual web development tools

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

WebStorm Mac version
Useful JavaScript development tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

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