1、簡介 node
字符集是一套符號和編碼的規則,不管是在oracle數據庫仍是在mysql數據庫,都存在字符集的選擇問題,並且若是在數據庫建立階段沒有正確選擇字符集,那麼可能在後期須要更換字符集,而字符集的更換是代價比較高的操做,也存在必定的風險,因此,咱們推薦在應用開始階段,就按照需求正確的選擇合適的字符集,避免後期沒必要要的調整。mysql
2、亂碼演示git
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,'雲中鶴'); Query OK, 1 row affected (0.00 sec) mysql> select * from test.table10; +------+-----------+ | id | names | +------+-----------+ | 1 | 雲中鶴 | +------+-----------+ 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 #客戶端來源數據使用的字符集 | character_set_connection | latin1 # 鏈接層字符集 | character_set_database | utf8 #當前選中數據庫的默認字符集 | character_set_filesystem | binary | character_set_results | latin1 #查詢結果字符集 | | character_set_server | utf8 #默認的內部操做字符集 | | character_set_system | utf8 #系統元數據(字段名等)字符集 | character_sets_dir | /usr/local/mysql/share/charsets/ | +--------------------------+----------------------------------+ 8 rows in set (0.00 sec)
3、亂碼解決辦法github
從上面能夠看出,set names latin1;改變了三個參數.. 只要作到客戶端,MySQL character-set-client,table charset三個字符集徹底一致就能夠保證必定不會有亂碼出現。sql
方式: 數據庫
1、在mysql命令行模式下執行set names xxx;vim
mysql> set names utf8; Query OK, 0 rows affected (0.01 sec)
2、登陸mysql的時候指定默認字符集bash
[root@node1 ~]# mysql -S /tmp/mysql.sock4 --defaults-character-set=utf8 #-S 指定多實例mysql的套接字文件, 使用--defaults-character-set 指定默認字符集。
3、 修改/etc/sysconfig/i18n 文件,在my.cnf不指定默認字符集的狀況下。服務器
vim /etc/sysconfig/i18n LANG='zh_CN.UTF-8' #若是my.cnf不指定,默認使用系統字符集
4、 修改my.cnf 文件,下面兩個字段在任意一個字段都是能夠的。網絡
[client] default-character-set=latin1
[mysql] default-character-set=latin1
前兩種1,2是臨時解決方案,後面兩種3,4是永久有效的方案
4、查看系統當前字符集設置,修改以後登錄mysql執行。show variables lile 'character_set%';
mysql> show variables like 'character_set%';#我修改的爲utf8,因此客戶端的三個參數都是utf8.你能夠自行設置字符集。 +--------------------------+----------------------------------+ | 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/ |
5、mysql經常使用字符集。執行命令show character set; 查看系統支持字符集。
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 | #經常使用 | 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 | #經常使用 | 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 |#經常使用 | 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 | #經常使用 | 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)
6、字符集選擇。
一、若是處理各類各樣的文字,發佈到不一樣語言國家地區,選擇Unicode。,對mysql對號utf-8。
二、只需中文,數據量很大,性能要求也高,選擇gbk.。
三、處理移動物聯網業務,選utf8mb4
建議在可以徹底知足應用的前提下,儘可能使用小的字符集。由於更小的字符集意味着可以節省空間、減小網絡傳輸字節數,同時因爲存儲空間的較小間接的提升了系統的性能。
7、服務器字符集選擇。
[mysqld] ... character-set-server=utf8 #添加這條語句,可設置服務器端字符集。
mysql服務端從新啓動後,這兩個參數會改變爲設定值。
| character_set_server | utf8 | character_set_database | utf8
8、將一種編碼的數據庫轉換爲另外一種編碼的數據。
alter database dbname character set xxx; #只能對之後的數據有效,對以前的數據無效。基本不使用
經常使用轉換數據庫字符集方案
mysqldump -S /tmp/mysql.sock4 --default-character-set=utf8 -d test > /data/test-`date +%F`.sql #一、導出表結構而不導出數據 vim /data/test-`date +%F`.sql DROP 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 ) ENGINE=InnoDB DEFAULT CHARSET=utf8; #二、這裏的CHARSET改成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 #三、導出數據內容 vim /data/test-data-`date +%F`.sql LOCK TABLES `table10` WRITE; set names utf8; #四、這一行是多加的,本身指定想要轉換的字符集 INSERT INTO `table10` VALUES (1,'雲中鶴'); UNLOCK TABLES; mysql> create database if not exists test; #五、建立數據庫,存儲轉換後的數據 Query OK, 1 row affected, 0 warning (0.00 sec) mysql -S /tmp/mysql.sock4 test < /data/test-`date +%F`.sql #六、導入表結構 mysql -S /tmp/mysql.sock4 test < /data/test-data-2015-09-25.sql #七、導入表數據
總結:
1、學好數據庫很是重要。
2、這篇博客原理性的東西未涉及,只是演示了一下解決方案,具體原理參考http://cenalulu.github.io/mysql/mysql-mojibake/
3、請你們指出不足,一我的接觸的方面太窄了,感受肚子裏墨水不多,經驗也很少,寫起來好難。。。好吧,可貴事情越作越容易。先寫到這裏吧