由于系统自带的MySQL默认字符集不是gbk,因此给数据库的推广应用以及中文程序的开发带来极大的不便,在没完没了的GBK和UTF8的转换过程中消耗了我们无数的精力以及系统的资源。
先将slack支持中文,然后重新编译MySQL,原来系统MySQL的要先卸载:
login:rootshell> removepkg mysqlshell> groupadd mysqlshell> cd /appshell> mkdir mysqlshell> chmod 744 mysqlshell> useradd -G mysql -s /bin/bash –p /app/mysql mysqlshell> chown -R mysql.mysql mysql
再下载MySQL4.x.x:
shell> gunzip cd mysql-VERSIONshell> CFLAGS="-O3 -mcpu=pentium3" /CXX=gcc /XXFLAGS="-O3 -mcpu=pentium3 -felide-constructors" /./configure --prefix=/app/mysql /--with--charset=gbk /--with-extra-charsets="gbk gb2312 big5 utf8"/--with-unix-socket-path=/etc/mysql.sock /--enable-local-infile /--enable-thread-safe-client /--enable-assembler /--with-client-ldflags=-all-static /--with-mysqld-ldflags=-all-static
//-mcpu 根据CPU类型优化编译,可以让你的MySQL表现更好。可选项目很多:i386, i486, i586, i686, pentium, pentium-mmx, pentiumpro, pentium2, pentium3, pentium4, k6, k6-2, k6-3, athlon, athlon-tbird, athlon-4, athlon-xp,athlon-mp,winchip-c6, winchip2 , c3。执行:shell> make。错误时候执行:shell> make clean。
再回上一步:
shell> make installshell> cp support-files/my-medium.cnf /etc/my.cnfshell> cd /app/mysqlshell> bin/mysql_install_db --user=rootshell> chown -R root .shell> chown -R mysql varshell> chgrp -R mysql .shell> ./bin/mysqld_safe --user=root --default-character-set=gbk &shell> ./bin/mysqladmin -u root password 'new-password'shell> ./bin/mysql -u root --default-character-set=gbk -pmysql> status...Server characterset: gbkDb characterset: gbkClient characterset: gbkConn. characterset: gbk....
看见characterset全是gbk就成功了。
在UTF8字符集的老数据库中,创建中文支持表脚本如下,对字段加上字符集说明:
CREATE TABLE `test`.`cn` (`zh` CHAR(10) CHARACTER SET gb2312 COLLATE gb2312_chinese_ci NOT NULL,`中文` INT(11) NOT NULL)ENGINE = MYISAM;
注:CHARACTER SET写GB2312和gbk都可以,gbk优于GB2312。
对于新创建的数据库加个默认字符集声明GBK,就不用建表时候每个字段声明了,这样看起来简单流畅,没有特殊的痕迹,建议多采用这种方法。
mysql> CREATE DATABASE dbCN DEFAULT CHARACTER SET gbk COLLATE gbk_chinese_ci;CREATE TABLE `dbCN`.`cn` (`zh` CHAR(10) NOT NULL,`中文` INT(11) NOT NULL)ENGINE = MYISAM;mysql> insert into cn values("真的?",1);
注:如果这些脚本用bin/mysql命令行是输入不了,可以用mysql query Browser或者编程执行。
shell> bin/mysql -u root --default-character-set=gbk -pmysql>use testmysql> select * from cn;+--------+------+| zh | 中文 |+--------+------+| 真的?| 1 |+--------+------+1 row in set (0.00 sec)-----------------------------
最后修改启动文件/etc/rc.d/rc.mysqld,改路径/app/mysql/bin/mysqld_safe,改路径/app/mysql/var/web.pid最后/app/mysql/bin/mysqld_safe 后面加入 --user=root --default-character-set=gbk

ACID attributes include atomicity, consistency, isolation and durability, and are the cornerstone of database design. 1. Atomicity ensures that the transaction is either completely successful or completely failed. 2. Consistency ensures that the database remains consistent before and after a transaction. 3. Isolation ensures that transactions do not interfere with each other. 4. Persistence ensures that data is permanently saved after transaction submission.

MySQL is not only a database management system (DBMS) but also closely related to programming languages. 1) As a DBMS, MySQL is used to store, organize and retrieve data, and optimizing indexes can improve query performance. 2) Combining SQL with programming languages, embedded in Python, using ORM tools such as SQLAlchemy can simplify operations. 3) Performance optimization includes indexing, querying, caching, library and table division and transaction management.

MySQL uses SQL commands to manage data. 1. Basic commands include SELECT, INSERT, UPDATE and DELETE. 2. Advanced usage involves JOIN, subquery and aggregate functions. 3. Common errors include syntax, logic and performance issues. 4. Optimization tips include using indexes, avoiding SELECT* and using LIMIT.

MySQL is an efficient relational database management system suitable for storing and managing data. Its advantages include high-performance queries, flexible transaction processing and rich data types. In practical applications, MySQL is often used in e-commerce platforms, social networks and content management systems, but attention should be paid to performance optimization, data security and scalability.

The relationship between SQL and MySQL is the relationship between standard languages and specific implementations. 1.SQL is a standard language used to manage and operate relational databases, allowing data addition, deletion, modification and query. 2.MySQL is a specific database management system that uses SQL as its operating language and provides efficient data storage and management.

InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB


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