mysql - 如何在 MySQL 中创建带重音的索引

Question

我有一个用 phpMyAdmin 管理的数据库。我有一个表来保存 verb tense 和 verb。看起来像这样:

Column | Type        | Collation         |  Attributes | Null | Default | Extra
-------+-------------+-------------------+-------------+------+---------+------
form   | varchar(50) | latin1_swedish_ci |             | No   |         |
verb   | varchar(50) | latin1_swedish_ci |             | Yes  | NULL    |

我创建了索引以加快访问速度:

Keyname     | Type  | Unique | Packed | Column | Cardinality | Collation | Null | Comment
------------+-------+--------+--------+--------+-------------+-----------+------+--------
verbs_index | BTREE | Yes    | No     | form   | 1           | A         |      |
            |       |        |        | verb   | 1           | A         | YES  |

这样做的目的是在一个动词和它的所有动词时态(form)之间建立关联，但是当我尝试插入一对(form)时，问题就来了,verb) 如果没有重音的形式已经存在，则带有重音。这些词与 MySql 相同，我收到错误:

Duplicate entry 'form-verb' for key 'verbs_index'.

我想插入:

insert into verbs values('o','verb1'); (without accent)
insert into verbs values('ó','verb1'); (with accent)

我一直在研究排序规则，并且我已经尝试过每个 latin 和 utf8。

Answer 1

“不区分大小写”的排序规则将忽略任何类型的变化来比较字符串。当然是情况。但它也会忽略变音符号。例如，o、O、Ô 和 ò 被认为是相等的。

要了解系统上可用的排序规则，请使用 SHOW COLLATION :

mysql> SHOW COLLATION;
+----------------------+----------+-----+---------+----------+---------+
| Collation            | Charset  | Id  | Default | Compiled | Sortlen |
+----------------------+----------+-----+---------+----------+---------+
[...]
| latin1_german1_ci    | latin1   |   5 |         | Yes      |       1 |
| latin1_swedish_ci    | latin1   |   8 | Yes     | Yes      |       1 |
| latin1_danish_ci     | latin1   |  15 |         | Yes      |       1 |
| latin1_german2_ci    | latin1   |  31 |         | Yes      |       2 |
| latin1_bin           | latin1   |  47 |         | Yes      |       1 |
| latin1_general_ci    | latin1   |  48 |         | Yes      |       1 |
| latin1_general_cs    | latin1   |  49 |         | Yes      |       1 |
| latin1_spanish_ci    | latin1   |  94 |         | Yes      |       1 |
| latin2_czech_cs      | latin2   |   2 |         | Yes      |       4 |
| latin2_general_ci    | latin2   |   9 | Yes     | Yes      |       1 |
| latin2_hungarian_ci  | latin2   |  21 |         | Yes      |       1 |
| latin2_croatian_ci   | latin2   |  27 |         | Yes      |       1 |
[...]

假设您要将表格排序规则更改为 latin1_general_cs(_cs 用于区分大小写——大小写 + 重音等等):

mysql> ALTER TABLE verbs COLLATE latin1_general_cs;