MySQL architecture
Preface
This environment is based on Centos 7.8 system to build MySQL-5.7.14 for
specific construction, please refer to MySQL-5.7.14 environment construction
MySQL character set includes two concepts: character set (CHARACTER) and collation (COLLATION):
View MySQL character set
mysql> show variables like 'character%';
+--------------------------+----------------------------+
| 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 (0.00 sec)
View MySQL character collation rules
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 |
| cp850_general_ci | cp850 | 4 | Yes | Yes | 1 |
| cp850_bin | cp850 | 80 | | Yes | 1 |
| hp8_english_ci | hp8 | 6 | Yes | Yes | 1 |
| hp8_bin | hp8 | 72 | | Yes | 1 |
| koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 |
| koi8r_bin | koi8r | 74 | | Yes | 1 |
| latin1_german1_ci | latin1 | 5 | | Yes | 1 |
| latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 |
... ...
1. What are the naming suffixes of MySQL character set? What does it mean?
MySQL character sequence naming rules are: start with the name of the character set corresponding to the character sequence, center the country name (or center general), and end with ci, cs, or bin.
- ci: meansCase insensitive
- cs: meansCase Sensitive
- bin means to compare according to binary coded value
Two, modify the MySQL character set
We modify the character set of the database by modifying the configuration file of the MySQL service, which takes effect globally to
view the character set of the current database
mysql> show variables like '%character%';
+--------------------------+----------------------------+
| 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 (0.00 sec)
Modify the database character set
#配置文件中添加设置内容
[root@mysql-server ~]# vim /etc/my.cnf
[mysqld]
character-set-server=utf8
[client]
default-character-set=utf8
Log out of the database, log in again, and check the character set of the database again
mysql> show variables like '%character%';
+--------------------------+----------------------------+
| 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/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
Note: character_set_filesystem default character set is binary, which is a fixed setting and cannot be modified