MySQL 5.5 將字符集從 utf8 升級為 utf8mb4

一、升級前。
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 | /home/sdkserver/local/mysql-5.5.43-linux2.6-x86_64/share/charsets/ |
+————————–+——————————————————————–+
8 rows in set (0.00 sec)

mysql> SHOW VARIABLES LIKE ‘collation%’;

+———————-+—————–+
| Variable_name | Value |
+———————-+—————–+
| collation_connection | utf8_general_ci |
| collation_database | utf8_unicode_ci |
| collation_server | utf8_unicode_ci |
+———————-+—————–+
3 rows in set (0.00 sec)

二、修改配置檔案。
開啓 MySQL 的配置檔案，將字符集的配置修改成如下：
[client]
default-character-set = utf8mb4

[mysql]
default-character-set = utf8mb4

[mysqld]
character-set-client-handshake = FALSE
character-set-server = utf8mb4
collation-server = utf8mb4_general_ci
init_connect=’SET NAMES utf8mb4′

三、升級後。
mysql> SHOW VARIABLES LIKE ‘character_set%’;

+————————–+——————————————————————–+
| 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 |
| character_sets_dir | /home/nieyong/local/mysql-5.5.43/share/charsets/ |
+————————–+——————————————————————–+
8 rows in set (0.00 sec)

mysql> SHOW VARIABLES LIKE ‘collation%’;

+———————-+——————–+
| Variable_name | Value |
+———————-+——————–+
| collation_connection | utf8mb4_general_ci |
| collation_database | utf8mb4_general_ci |
| collation_server | utf8mb4_general_ci |
+———————-+——————–+
3 rows in set (0.00 sec)