MariaDB修改編碼格式

1. 通過set修改value字段
2. 登錄MySQL，使用 show variables like 'character%';
3. 查看當前編碼格式
5. 使用 set character_set_client = 'utf8mb4';
6. 直接修改variable_name的value

1. Mariadb通過配置文件修改編碼

2. 1、登錄MySQL，使用

   SHOW VARIABLES LIKE 'character%';

   查看當前使用的字符集，應該有好幾個不是UTF-8格式。

   2、要修改的配置文件位於 /etc/my.cnf.d目錄下：

   client.cnf

   在[client]字段里加入

   default-character-set=utf8

   server.cnf

   在[mysqld]字段里加入

   character-set-server=utf8

   systemctl restart mariadb 配置生效，修改後的效果如下：

3. 修改字段編碼格式：

4. 先查看下編碼：

   MariaDB [(none)]>  SHOW VARIABLES WHERE Variable_name LIKE 'character\_set\_%' OR Variable_name LIKE 'collation%';
   +--------------------------+-------------------+
   | 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              |
   | collation_connection     | utf8_general_ci   |
   | collation_database       | latin1_swedish_ci |
   | collation_server         | latin1_swedish_ci |
   +--------------------------+-------------------+
   10 rows in set (0.00 sec)
   

   修改/etc/my.cnf.d/server.cnf
   [mysqld]

   [mysqld]
   character_set_server=utf8mb4
   collation-server=utf8mb4_unicode_ci
   init_connect='SET NAMES utf8mb4'
   skip-character-set-client-handshake=true
   

   重啓DB：

   systemctl restart mariadb

   再次查看編碼：

   MariaDB [(none)]> SHOW VARIABLES WHERE Variable_name LIKE 'character\_set\_%' OR Variable_name LIKE 'collation%';
   +--------------------------+--------------------+
   | Variable_name            | Value              |
   +--------------------------+--------------------+
   | character_set_client     | utf8mb4            |
   | character_set_connection | utf8mb4            |
   | character_set_database   | utf8mb4            |
   | character_set_filesystem | binary             |
   | character_set_results    | utf8mb4            |
   | character_set_server     | utf8mb4            |
   | character_set_system     | utf8               |
   | collation_connection     | utf8mb4_unicode_ci |
   | collation_database       | utf8mb4_unicode_ci |
   | collation_server         | utf8mb4_unicode_ci |
   +--------------------------+--------------------+
   10 rows in set (0.00 sec)
   

   修改DB的默認編碼：

   ALTER DATABASE XX_db CHARACTER SET utf8mb4;

   1.查看數據庫編碼格式

   1	mysql> show variables like 'character_set_database';

    2.查看數據表的編碼格式

   1	mysql> show create table <表名>;

    3.創建數據庫時指定數據庫的字符集

   mysql>create database <數據庫名> character set utf8;

   4.創建數據表時指定數據表的編碼格式

   create table tb_books (
       name varchar(45) not null,
       price double not null,
       bookCount int not null,
       author varchar(45) not null ) default charset = utf8;

   5.修改數據庫的編碼格式

   mysql>alter database <數據庫名> character set utf8;

   6.修改DB的默認編碼：

   ALTER DATABASE XX_db CHARACTER SET utf8mb4;

   7.修改表中字段編碼

   ALTER TABLE 表名 MODIFY `字段` TEXT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

    8.添加外鍵

   mysql>alter table tb_product add constraint fk_1 foreign key(factoryid) references tb_factory(factoryid);
   mysql>alter table <表名> add constraint <外鍵名> foreign key<字段名> REFERENCES <外表表名><字段名>;

   9.刪除外鍵

   mysql>alter table tb_people drop foreign key fk_1;
   mysql>alter table <表名> drop foreign key <外鍵名>;