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mysql在通过导入sql文件可能会出现下面二个问题: 1.如果sql文件过大,会出现"MySQL server has gone away"问题;
2.如果sql文件数据有中文,会出现乱码 解决问题: 问题1:出现MySQL server has gone away"问题,是因为mysql默认的"max_allowed_packet"变量值过小.查看目前配置
show VARIABLES like '%max_allowed_packet%';
显示的结果为: +--------------------+---------+| Variable_name | Value |+--------------------+---------+| max_allowed_packet | 1048576 |+--------------------+---------+
说明目前的配置是:1048576/1024/1024 = 1M 修改max_allowed_packet值:
方法1: SET GLOBAL max_allowed_packet = 500*1024*1024;(经测试无效)
方法2: 直接修改配置文件,重启mysql windows中修改my.ini文件,在linux中修改my.cnf文件. C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.5/my.ini(安装mysql时的,指定的数据文件目录)
重启mysql后,在查看修改后的max_allowed_packet值
问题2:登录时指定字符集编码 mysql -uroot -P3308 -p123456 - -default-character-set=utf8 (-P是指指定端口号) 最后通过source命令 即可成功导入: source E:ydj/test.sql
作者 LoveJavaYDJ bitsCN.com

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

The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.

The steps to build a MySQL database include: 1. Create a database and table, 2. Insert data, and 3. Conduct queries. First, use the CREATEDATABASE and CREATETABLE statements to create the database and table, then use the INSERTINTO statement to insert the data, and finally use the SELECT statement to query the data.

MySQL is suitable for beginners because it is easy to use and powerful. 1.MySQL is a relational database, and uses SQL for CRUD operations. 2. It is simple to install and requires the root user password to be configured. 3. Use INSERT, UPDATE, DELETE, and SELECT to perform data operations. 4. ORDERBY, WHERE and JOIN can be used for complex queries. 5. Debugging requires checking the syntax and use EXPLAIN to analyze the query. 6. Optimization suggestions include using indexes, choosing the right data type and good programming habits.


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