MySQL字符集
-- ----------------- ------------- Linux系统字符集编码 ------------------------------ ----------------
#1.命令行临时修改 :
LANG=us_EN.UTF-8
LANG=zh_CN.UTF-8
临时修改报错命令为应文 : LANG=us_EN.UTF-8
#2.修改系统字符集
Centos6 永久修改：[root@localhost ~]# vim /etc/sysconfig/i18n
Centos7 永久修改：[root@localhost ~]# vim /etc/locale.conf
-- ------- ---------------- ----------- MySQL字符集指定 --------------- ------------------------ ---
-- ---------- ----------------- ----- ----- 方法一 ------------- -----------------------------------
#编译之前指定
cmake .
-DDEFAULT_CHARSET=UTF8 \
-DDEFAULT_COLLATION=UTF8_GENERAL_CI
-- ---------- ----------------- ----- ----- 方法二 ------------- -------------------------
#配置文件指定
#1.修改配置文件
[mysqld]
character-set-server=utf8
collation-server=utf8_general_ci
[client]
default-character-set=utf8
[mysql]
default-character-set=utf8
#2. 重启服务
[root@db01 ~]# systemctl restart mysqld
#3. 查看修改结果：
mysql> show variables like '%char%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.07 sec)
-- ---------- ----------------- ----- ----- 方法三 ------------- -------------------------
#创建数据库指定字符集和校验规则
mysql> CREATE DATABASE test01 CHARACTER SET utf8 COLLATE utf8_general_ci;
Query OK, 1 row affected (0.00 sec)
mysql> -- 修改数据库字符集及校验规则
mysql> ALTER DATABASE test01 CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;
Query OK, 1 row affected (0.00 sec)
mysql> -- 查看
mysql> SHOW CREATE DATABASE test01;
+----------+--------------------------------------------------------------------+
| Database | Create Database |
+----------+--------------------------------------------------------------------+
| test01 | CREATE DATABASE `test01` /*!40100 DEFAULT CHARACTER SET utf8mb4 */ |
+----------+--------------------------------------------------------------------+
1 row in set (0.00 sec)
#创建数据表指定字符集及校验规则
mysql> CREATE TABLE p1(
id int,
name varchar(20)
) CHARACTER SET utf8 COLLATE utf8_general_ci;
Query OK, 0 rows affected (0.01 sec)
mysql> -- 修改表的字符集及校验规则
mysql> ALTER TABLE p1 CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> -- 查看
mysql> SHOW CREATE TABLE p1\G
*************************** 1. row ***************************
Table: p1
Create Table: CREATE TABLE `p1` (
`id` int(11) DEFAULT NULL,
`name` varchar(20) CHARACTER SET utf8 DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
1 row in set (0.00 sec)
#一个表里面不可能出现同名不同大小写的字段
#查看校验规则
mysql> show collation;
+--------------------------+----------+-----+---------+----------+---------+
| Collation | Charset | Id | Default | Compiled | Sortlen |
+--------------------------+----------+-----+---------+----------+---------+
| big5_chinese_ci | big5 | 1 | Yes | Yes | 1 |
| big5_bin | big5 | 84 | | Yes | 1 |
| dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 |
| dec8_bin | dec8 | 69 | | Yes | 1 |
.........
#校验规则区别
1.ci结尾的校验规则不区分大小写
2.bin和cs结尾的校验规则区分大小写
#数据库查看字符集
mysql> show charset;
+----------+---------------------------------+---------------------+--------+
| 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 |
| 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 |
| 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 |
| 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 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| utf16le | UTF-16LE Unicode | utf16le_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 |
| gb18030 | China National Standard GB18030 | gb18030_chinese_ci | 4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)
#字符集utf8和utf8mb4之间的区别？
utf8不支持emoji表情而utf8mb4支持。
