Loading... MySQL在 5.5.3 之后增加了 utf8mb4 字符编码,mb4即 most bytes 4。简单说 utf8mb4 是 utf8 的超集并完全兼容utf8,能够用四个字节存储更多的字符。 有时,我们需要在mysql中存放emoji表情,emoji表情是1个字符占4个字节,而utf8编码只支持1-3个字节的字符,所以utf8编码下,如果直接存储表情,数据库存储会失败,所以需要改成utf8mb4。 需要修改:库、表、字段 修改数据库字符集: ```shell ALTER DATABASE db_name DEFAULT CHARACTER SET character_name [COLLATE ...];如:ALTER DATABASE test DEFAULT CHARACTER SET utf8mb4; ``` 把表默认的字符集和所有字符列改为新的字符集: ```shell ALTER TABLE tbl_name CONVERT TO CHARACTER SET character_name [COLLATE ...]如:ALTER TABLE logtest CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8_general_ci; ``` 只是修改表的默认字符集: ```shell ALTER TABLE tbl_name DEFAULT CHARACTER SET character_name [COLLATE...];如:ALTER TABLE logtest DEFAULT CHARACTER SET utf8mb4 COLLATE utf8_general_ci; ``` 修改字段的字符集: ```shell ALTER TABLE tbl_name CHANGE c_name c_name CHARACTER SET character_name [COLLATE ...];如:ALTER TABLE logtest CHANGE title title VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_general_ci; ``` 查看数据库编码: ```shell SHOW CREATE DATABASE db_name; ``` 查看表编码: ```shell SHOW CREATE TABLE tbl_name; ``` 查看字段编码: ```shell | SHOW FULL COLUMNS FROM tbl_name; | ``` 查看当前数据库编码: ```shell SHOW VARIABLES LIKE 'character_set_%'; ``` mysql-connector-java驱动包在5.1.13+才支持utf8mb4 ```shell set global character_set_server=utf8mb4; set global character_set_database=utf8mb4; set global character_set_client=utf8mb4; set global character_set_connection=utf8mb4; ``` 修改配置文件: ```shell 如:default-character-set = utf8mb4 character_set_server = utf8mb4 character-set-client-handshake = FALSE collation-server = utf8mb4_unicode_ci init_connect='SET NAMES utf8mb4' ``` 重启mysql: 有些情况下修改后并不及时生效,需要重启mysql 最后修改:2021 年 12 月 15 日 11 : 00 AM © 允许规范转载 赞赏 如果觉得我的文章对你有用,请随意赞赏 赞赏作者 支付宝微信
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