如何将 MySQL 的 utf8 默认排序规则设置为 utf8_unicode_ci?

How can I set MySQL's default collation for utf8 to utf8_unicode_ci?

我正在将数据库转换为 utf8 字符集和 utf8_unicode_ci 排序规则。将 table 的字符集更改为 utf8 时,MySQL 会自动将 table 的列转换为 utf8 的默认排序规则:utf_general_ci。我不想运行数百个alter column命令将每一列都转换成utf8_unicode_ci,所以我可以将utf8的默认排序规则设置为utf8_unicode_ci吗,如information_schema ]?:

SELECT * FROM information_schema.COLLATIONS WHERE CHARACTER_SET_NAME = 'utf8';

+---------------------------+--------------------+-----+------------+-------------+---------+
| COLLATION_NAME            | CHARACTER_SET_NAME | ID  | IS_DEFAULT | IS_COMPILED | SORTLEN |
+---------------------------+--------------------+-----+------------+-------------+---------+
| utf8_general_ci           | utf8               |  33 | Yes        | Yes         |       1 |
| utf8_bin                  | utf8               |  83 |            | Yes         |       1 |
| utf8_unicode_ci           | utf8               | 192 |            | Yes         |       8 |
| utf8_icelandic_ci         | utf8               | 193 |            | Yes         |       8 |
| utf8_latvian_ci           | utf8               | 194 |            | Yes         |       8 |
| utf8_romanian_ci          | utf8               | 195 |            | Yes         |       8 |
| utf8_slovenian_ci         | utf8               | 196 |            | Yes         |       8 |
| utf8_polish_ci            | utf8               | 197 |            | Yes         |       8 |
| utf8_estonian_ci          | utf8               | 198 |            | Yes         |       8 |
| utf8_spanish_ci           | utf8               | 199 |            | Yes         |       8 |
| utf8_swedish_ci           | utf8               | 200 |            | Yes         |       8 |
| utf8_turkish_ci           | utf8               | 201 |            | Yes         |       8 |
| utf8_czech_ci             | utf8               | 202 |            | Yes         |       8 |
| utf8_danish_ci            | utf8               | 203 |            | Yes         |       8 |
| utf8_lithuanian_ci        | utf8               | 204 |            | Yes         |       8 |
| utf8_slovak_ci            | utf8               | 205 |            | Yes         |       8 |
| utf8_spanish2_ci          | utf8               | 206 |            | Yes         |       8 |
| utf8_roman_ci             | utf8               | 207 |            | Yes         |       8 |
| utf8_persian_ci           | utf8               | 208 |            | Yes         |       8 |
| utf8_esperanto_ci         | utf8               | 209 |            | Yes         |       8 |
| utf8_hungarian_ci         | utf8               | 210 |            | Yes         |       8 |
| utf8_sinhala_ci           | utf8               | 211 |            | Yes         |       8 |
| utf8_german2_ci           | utf8               | 212 |            | Yes         |       8 |
| utf8_croatian_mysql561_ci | utf8               | 213 |            | Yes         |       8 |
| utf8_unicode_520_ci       | utf8               | 214 |            | Yes         |       8 |
| utf8_vietnamese_ci        | utf8               | 215 |            | Yes         |       8 |
| utf8_general_mysql500_ci  | utf8               | 223 |            | Yes         |       1 |
| utf8_croatian_ci          | utf8               | 576 |            | Yes         |       8 |
| utf8_myanmar_ci           | utf8               | 577 |            | Yes         |       8 |
+---------------------------+--------------------+-----+------------+-------------+---------+

记下 IS_DEFAULT 列。

另请注意,我不是在询问如何使用 ALTER!

转换数据库、table 或列

另外添加 collation_server = utf8_unicode_ci 到 my.cnf 不起作用。

我建议您创建一个具有您想要的排序规则的数据库和 运行 一个用于复制所有表和数据的脚本(在临时服务器中,我建议您在临时服务器中执行此操作 不在产品中),如果一切正常,请检查暂存,然后在产品中进行。

每个 table 需要一个 ALTER,而不是每列 (Reference):

ALTER TABLE foo CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;

您可以生成所有的alters,然后手动复制它们来执行它们。像

SELECT CONCAT("ALTER TABLE ", table_schema, ".", table_name,
              " CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;
       ")
    FROM information_schema.tables
    WHERE table_schema NOT IN ('mysql', 'information_schema',
                               'performance_schema', 'sys_schema');

但我建议你CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_520_ci这样你就可以处理所有的中文,加上表情符号。

我希望你做到了 CONVERT TO,而不仅仅是 MODIFY COLUMN。前者转换字符;后者会弄乱 table.

中已有的任何 8 位字符

如果您在 VARCHAR(255) 上有索引,就会出现 utf8mb4 问题。如果可行,将大小缩小到 191 或更小。

例子

mysql> SHOW CREATE TABLE iidr\G
*************************** 1. row ***************************
       Table: iidr
Create Table: CREATE TABLE `iidr` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `key2` int(10) unsigned NOT NULL,
  `vc` varchar(99) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `key2` (`key2`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

mysql> SHOW FULL COLUMNS FROM iidr;
+-------+------------------+-----------------+------+-----+---------+----------------+---------------------------------+---------+
| Field | Type             | Collation       | Null | Key | Default | Extra          | Privileges                      | Comment |
+-------+------------------+-----------------+------+-----+---------+----------------+---------------------------------+---------+
| id    | int(10) unsigned | NULL            | NO   | PRI | NULL    | auto_increment | select,insert,update,references |         |
| key2  | int(10) unsigned | NULL            | NO   | UNI | NULL    |                | select,insert,update,references |         |
| vc    | varchar(99)      | utf8_general_ci | YES  |     | NULL    |                | select,insert,update,references |         |
+-------+------------------+-----------------+------+-----+---------+----------------+---------------------------------+---------+
3 rows in set (0.00 sec)

mysql> ALTER TABLE iidr CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_520_ci;
Query OK, 2 rows affected (0.14 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> SHOW FULL COLUMNS FROM iidr;
+-------+------------------+------------------------+------+-----+---------+----------------+---------------------------------+---------+
| Field | Type             | Collation              | Null | Key | Default | Extra          | Privileges                      | Comment |
+-------+------------------+------------------------+------+-----+---------+----------------+---------------------------------+---------+
| id    | int(10) unsigned | NULL                   | NO   | PRI | NULL    | auto_increment | select,insert,update,references |         |
| key2  | int(10) unsigned | NULL                   | NO   | UNI | NULL    |                | select,insert,update,references |         |
| vc    | varchar(99)      | utf8mb4_unicode_520_ci | YES  |     | NULL    |                | select,insert,update,references |         |
+-------+------------------+------------------------+------+-----+---------+----------------+---------------------------------+---------+
3 rows in set (0.00 sec)

mysql> SHOW CREATE TABLE iidr\G
*************************** 1. row ***************************
       Table: iidr
Create Table: CREATE TABLE `iidr` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `key2` int(10) unsigned NOT NULL,
  `vc` varchar(99) COLLATE utf8mb4_unicode_520_ci DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `key2` (`key2`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_520_ci
1 row in set (0.00 sec)