(1) 最简单的修改方法,就是修改mysql的my.ini文件中的字符集键值, 如 default-character-set = utf8 character_set_server = utf8 修改完后,重启mysql的服务,service mysql restart 使用 mysql SHOW VARIABLES LIKE 'character%';查看,发现数据库编码均
(1) 最简单的修改方法,就是修改mysql的my.ini文件中的字符集键值,
如 default-character-set = utf8
character_set_server = utf8
修改完后,重启mysql的服务,service mysql restart
使用 mysql> SHOW VARIABLES LIKE 'character%';查看,发现数据库编码均已改成utf8
<ol> <li><span>+--------------------------+---------------------------------+ </span></li> <li><span>| Variable_name | Value | </span></li> <li><span>+--------------------------+---------------------------------+ </span></li> <li><span>| character_set_client | utf8 | </span></li> <li><span>| character_set_connection | utf8 | </span></li> <li><span>| character_set_database | utf8 | </span></li> <li><span>| character_set_filesystem | binary | </span></li> <li><span>| character_set_results | utf8 | </span></li> <li><span>| character_set_server | utf8 | </span></li> <li><span>| character_set_system | utf8 | </span></li> <li><span>| character_sets_dir | D:"mysql-5.0.37"share"charsets" | </span></li> <li><span>+--------------------------+---------------------------------+ </span></li> </ol>
(2) 还有一种修改mysql默认字符集的方法,就是使用mysql的命令
<ol> <li><span><span>mysql</span><span>></span><span> SET </span><span>character_set_client</span><span> = </span><span>utf8</span><span> ; </span></span></li> <li> <span>mysql</span><span>></span><span> SET </span><span>character_set_connection</span><span> = </span><span>utf8</span><span> ; </span> </li> <li> <span>mysql</span><span>></span><span> SET </span><span>character_set_database</span><span> = </span><span>utf8</span><span> ; </span> </li> <li> <span>mysql</span><span>></span><span> SET </span><span>character_set_results</span><span> = </span><span>utf8</span><span> ; </span> </li> <li> <span>mysql</span><span>></span><span> SET </span><span>character_set_server</span><span> = </span><span>utf8</span><span> ; </span> </li> <li><span> </span></li> <li> <span>mysql</span><span>></span><span> SET </span><span>collation_connection</span><span> = </span><span>utf8</span><span> ; </span> </li> <li> <span>mysql</span><span>></span><span> SET </span><span>collation_database</span><span> = </span><span>utf8</span><span> ; </span> </li> <li> <span>mysql</span><span>></span><span> SET </span><span>collation_server</span><span> = </span><span>utf8</span><span> ; </span> </li> </ol>
一般就算设置了表的mysql默认字符集为utf8并且通过UTF-8编码发送查询,你会发现存入数据库的仍然是乱码。问题就出在这个connection连接层上。解决方法是在发送查询前执行一下下面这句:
<ol><li><span>SET NAMES 'utf8'; </span></li></ol>
它相当于下面的三句指令:
<ol> <li><span><span>SET </span><span>character_set_client</span><span> = </span><span>utf8</span><span>; </span></span></li> <li> <span>SET </span><span>character_set_results</span><span> = </span><span>utf8</span><span>; </span> </li> <li> <span>SET </span><span>character_set_connection</span><span> = </span><span>utf8</span><span>; </span> </li> </ol>

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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