更改网站主题,造价员证在哪个网站上查询,网站设计展示,网站制作网页推荐阅读#xff1a;闭关修炼21天#xff0c;“啃完”283页pdf#xff0c;我终于4面拿下字节跳动offer肺炎在家“闭关”#xff0c;阿里竟发来视频面试#xff0c;4面顺利拿下offer字符集是一套符号和编码的规则#xff0c;不论是在oracle数据库还是在mysql数据库#x…推荐阅读闭关修炼21天“啃完”283页pdf我终于4面拿下字节跳动offer肺炎在家“闭关”阿里竟发来视频面试4面顺利拿下offer字符集是一套符号和编码的规则不论是在oracle数据库还是在mysql数据库都存在字符集的选择问题而且如果在数据库创建阶段没有正确选择字符集那么可能在后期需要更换字符集而字符集的更换是代价比较高的操作也存在一定的风险所以我们推荐在应用开始阶段就按照需求正确的选择合适的字符集避免后期不必要的调整。实战1、安装MySQL数据库2、乱码演示mysql show variables like character_set%;------------------------------------------------------------| Variable_name | Value |------------------------------------------------------------| character_set_client | utf8 || character_set_connection | utf8 || character_set_database | utf8 || character_set_filesystem | binary || character_set_results | utf8 || character_set_server | utf8 || character_set_system | utf8 || character_sets_dir | /usr/local/mysql/share/charsets/ |------------------------------------------------------------8 rows in set (0.00 sec) mysql insert into test.table10 values (1,云中鹤);Query OK, 1 row affected (0.00 sec) mysql select * from test.table10;-----------------| id | names |-----------------| 1 | 云中鹤 |-----------------1 row in set (0.00 sec) mysql set names latin1;Query OK, 0 rows affected (0.00 sec) mysql select * from test.table10;-------------| id | names |-------------| 1 | ??? |-------------1 row in set (0.00 sec) mysql show variables like character_set%;------------------------------------------------------------| Variable_name | Value |------------------------------------------------------------| character_set_client | latin1 #客户端来源数据使用的字符集 | character_set_connection | latin1 # 连接层字符集| character_set_database | utf8 #当前选中数据库的默认字符集 | character_set_filesystem | binary | character_set_results | latin1 #查询结果字符集 || character_set_server | utf8 #默认的内部操作字符集 || character_set_system | utf8 #系统元数据(字段名等)字符集 | character_sets_dir | /usr/local/mysql/share/charsets/ |------------------------------------------------------------8 rows in set (0.00 sec)乱码解决办法从上面可以看出set names latin1;改变了三个参数.. 只要做到客户端MySQL character-set-clienttable charset三个字符集完全一致就可以保证一定不会有乱码出现。方式:​ 1、在mysql命令行模式下执行set names xxx; mysql set names utf8; Query OK, 0 rows affected (0.01 sec)​ 2、登录mysql的时候指定默认字符集 [rootnode1 ~]# mysql -S /tmp/mysql.sock4 --defaults-character-setutf8 #-S 指定多实例mysql的套接字文件 使用--defaults-character-set 指定默认字符集。​ 3、 修改/etc/sysconfig/i18n 文件在my.cnf不指定默认字符集的情况下。 vim /etc/sysconfig/i18n LANGzh_CN.UTF-8 #如果my.cnf不指定默认使用系统字符集​ 4、 修改my.cnf 文件下面两个字段在任意一个字段都是可以的。 [client] default-character-setlatin1 [mysql] default-character-setlatin1​ 前两种1,2是临时解决方案后面两种3,4是永久有效的方案查看字符集1、查看系统当前字符集设置修改之后登陆mysql执行。show variables lile character_set%;mysql show variables like character_set%;#我修改的为utf8所以客户端的三个参数都是utf8.你可以自行设置字符集。------------------------------------------------------------| Variable_name | Value |------------------------------------------------------------| character_set_client | utf8 || character_set_connection | utf8 || character_set_database | utf8 || character_set_filesystem | binary || character_set_results | utf8 || character_set_server | utf8 || character_set_system | utf8 || character_sets_dir | /usr/local/mysql/share/charsets/ |2、mysql常用字符集。执行命令show character set; 查看系统支持字符集。mysql show character set;--------------------------------------------------------------------| Charset | Description | Default collation | Maxlen |--------------------------------------------------------------------| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 || dec8 | DEC West European | dec8_swedish_ci | 1 || cp850 | DOS West European | cp850_general_ci | 1 || hp8 | HP West European | hp8_english_ci | 1 || koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 || latin1 | cp1252 West European | latin1_swedish_ci | 1 | #常用| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 || swe7 | 7bit Swedish | swe7_swedish_ci | 1 || ascii | US ASCII | ascii_general_ci | 1 || ujis | EUC-JP Japanese | ujis_japanese_ci | 3 || sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 || hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 || tis620 | TIS620 Thai | tis620_thai_ci | 1 || euckr | EUC-KR Korean | euckr_korean_ci | 2 || koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 || gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 || greek | ISO 8859-7 Greek | greek_general_ci | 1 || cp1250 | Windows Central European | cp1250_general_ci | 1 || gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | #常用| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 || armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 || utf8 | UTF-8 Unicode | utf8_general_ci | 3 |#常用| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 || cp866 | DOS Russian | cp866_general_ci | 1 || keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 || macce | Mac Central European | macce_general_ci | 1 || macroman | Mac West European | macroman_general_ci | 1 || cp852 | DOS Central European | cp852_general_ci | 1 || latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 || utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 | #常用| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 || utf16 | UTF-16 Unicode | utf16_general_ci | 4 || cp1256 | Windows Arabic | cp1256_general_ci | 1 || cp1257 | Windows Baltic | cp1257_general_ci | 1 || utf32 | UTF-32 Unicode | utf32_general_ci | 4 || binary | Binary pseudo charset | binary | 1 || geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 || cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 || eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |--------------------------------------------------------------------39 rows in set (0.00 sec)字符集选择​ 1、如果处理各种各样的文字发布到不同语言国家地区选择Unicode。对mysql对号utf-8。​ 2、只需中文数据量很大性能要求也高选择gbk.。​ 3、处理移动物联网业务选utf8mb4​ 建议在能够完全满足应用的前提下尽量使用小的字符集。因为更小的字符集意味着能够节省空间、减少网络传输字节数同时由于存储空间的较小间接的提高了系统的性能。服务器字符集设置[mysqld]...character-set-serverutf8 #添加这条语句可设置服务器端字符集。mysql服务端重新启动后这两个参数会改变为设定值。| character_set_server | utf8 | character_set_database | utf8切换字符集将一种编码的数据库转换为另一种编码的数据。alter database dbname character set xxx; #只能对以后的数据有效对之前的数据无效。基本不使用常用转换数据库字符集方案mysqldump -S /tmp/mysql.sock4 --default-character-setutf8 -d test /data/test-date %F.sql #1、导出表结构而不导出数据vim /data/test-date %F.sqlDROP TABLE IF EXISTS table10;/*!40101 SET saved_cs_client character_set_client */;/*!40101 SET character_set_client utf8 */;CREATE TABLE table10 ( id int(11) DEFAULT NULL, names char(20) DEFAULT NULL) ENGINEInnoDB DEFAULT CHARSETutf8; #2、这里的CHARSET改为你想要修改的字符集mysqldump -S /tmp/mysql.sock4 --extended-insert --no-create-info test /data/test-data-date %F.sql #3、导出数据内容vim /data/test-data-date %F.sqlLOCK TABLES table10 WRITE;set names utf8; #4、这一行是多加的自己指定想要转换的字符集INSERT INTO table10 VALUES (1,云中鹤);UNLOCK TABLES;mysql create database if not exists test; #5、创建数据库存储转换后的数据Query OK, 1 row affected, 0 warning (0.00 sec)mysql -S /tmp/mysql.sock4 test /data/test-date %F.sql #6、导入表结构mysql -S /tmp/mysql.sock4 test /data/test-data-2015-09-25.sql #7、导入表数据最后这是在15年的时候自己学习MySQL的笔记今天再拿出来分享下作者Real_man链接https://juejin.im/post/5ca55f13f265da309651a80a来源掘金