utf8的大小写敏感性测试及其修改方法
# 测试utf8的大小写敏感性及其修改方法 -- 以下是utf8不区分大小写 1 # 修改数据库: 2 ALTER DATABASE database_name CHARACTER SET = utf8 COLLATE = utf8_general_ci; 3 # 修改表: 4 ALTER TABLE table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci; 5 # 修改表字段: 6 ALTER TABLE table_name CHANGE column_name column_name VARCHAR(191) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL; -- 以下是utf8区分大小写 1 # 修改数据库: 2 ALTER DATABASE database_name CHARACTER SET = utf8 COLLATE = utf8_bin; 3 # 修改表: 4 ALTER TABLE table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_bin; 5 # 修改表字段: 6 ALTER TABLE table_name CHANGE column_name column_name VARCHAR(191) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL; -- 1、删除库 drop database if exists db2019; mysql> drop database if exists db2019; Query OK, 0 rows affected, 1 warning (0.00 sec) -- 2、创建字符集为utf8的库 create database db2019 DEFAULT CHARACTER SET utf8; mysql> create database db2019 DEFAULT CHARACTER SET utf8; Query OK, 1 row affected (0.00 sec) -- 3、查看建库语句 show create database db2019; mysql> show create database db2019; +----------+-----------------------------------------------------------------+ | Database | Create Database | +----------+-----------------------------------------------------------------+ | db2019 | CREATE DATABASE `db2019` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+-----------------------------------------------------------------+ 1 row in set (0.00 sec) -- 4、创建测试表和数据 use db2019; -- drop table if exists tbl_test ; create table tbl_test ( id bigint(20) NOT NULL AUTO_INCREMENT, name varchar(20) NOT NULL, PRIMARY KEY (id), KEY idx_name (name) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 ; -- 5、查看创建表的语句 -- use db2019; show create table tbl_testG; mysql> show create table tbl_testG; *************************** 1. row *************************** Table: tbl_test Create Table: CREATE TABLE `tbl_test` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `name` varchar(20) NOT NULL, PRIMARY KEY (`id`), KEY `idx_name` (`name`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 1 row in set (0.00 sec) ERROR: No query specified -- 6、查看默认字符集 -- 方法1、show variables like '%character%'; mysql> show variables like '%character%'; +--------------------------+----------------------------+ | 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 | /usr/share/mysql/charsets/ | +--------------------------+----------------------------+ 8 rows in set (0.00 sec) -- 方法2、show variables like 'collation%'; mysql> show variables like 'collation%'; +----------------------+--------------------+ | Variable_name | Value | +----------------------+--------------------+ | collation_connection | utf8_general_ci | | collation_database | utf8_general_ci | | collation_server | utf8_general_ci | +----------------------+--------------------+ 3 rows in set (0.00 sec) -- 8、查看默认校对规则 show collation like 'utf8%'; mysql> show collation like 'utf8%'; +--------------------------+---------+-----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +--------------------------+---------+-----+---------+----------+---------+ | utf8_general_ci | utf8 | 33 | Yes | Yes | 1 | | utf8_bin | utf8 | 83 | | Yes | 1 | | utf8_bin | 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_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_general_ci | utf8 | 45 | Yes | Yes | 1 | | utf8_bin | utf8 | 46 | | Yes | 1 | | utf8_bin | utf8 | 224 | | Yes | 8 | | utf8_icelandic_ci | utf8 | 225 | | Yes | 8 | | utf8_latvian_ci | utf8 | 226 | | Yes | 8 | | utf8_romanian_ci | utf8 | 227 | | Yes | 8 | | utf8_slovenian_ci | utf8 | 228 | | Yes | 8 | | utf8_polish_ci | utf8 | 229 | | Yes | 8 | | utf8_estonian_ci | utf8 | 230 | | Yes | 8 | | utf8_spanish_ci | utf8 | 231 | | Yes | 8 | | utf8_swedish_ci | utf8 | 232 | | Yes | 8 | | utf8_turkish_ci | utf8 | 233 | | Yes | 8 | | utf8_czech_ci | utf8 | 234 | | Yes | 8 | | utf8_danish_ci | utf8 | 235 | | Yes | 8 | | utf8_lithuanian_ci | utf8 | 236 | | Yes | 8 | | utf8_slovak_ci | utf8 | 237 | | Yes | 8 | | utf8_spanish2_ci | utf8 | 238 | | Yes | 8 | | utf8_roman_ci | utf8 | 239 | | Yes | 8 | | utf8_persian_ci | utf8 | 240 | | Yes | 8 | | utf8_esperanto_ci | utf8 | 241 | | Yes | 8 | | utf8_hungarian_ci | utf8 | 242 | | Yes | 8 | | utf8_sinhala_ci | utf8 | 243 | | Yes | 8 | | utf8_german2_ci | utf8 | 244 | | Yes | 8 | | utf8_croatian_ci | utf8 | 245 | | Yes | 8 | | utf8_unicode_520_ci | utf8 | 246 | | Yes | 8 | | utf8_vietnamese_ci | utf8 | 247 | | Yes | 8 | +--------------------------+---------+-----+---------+----------+---------+ 53 rows in set (0.00 sec) mysql> -- 9、插入测试数据 -- use db2019; insert into tbl_test(name) values('aaa'); insert into tbl_test(name) values('bbb'); insert into tbl_test(name) values('AAA'); insert into tbl_test(name) values('BBB'); mysql> select * from tbl_test; +----+------+ | id | name | +----+------+ | 1 | aaa | | 3 | AAA | | 2 | bbb | | 4 | BBB | +----+------+ 4 rows in set (0.00 sec) mysql> select * from tbl_test where name='aaa'; +----+------+ | id | name | +----+------+ | 1 | aaa | | 3 | AAA | +----+------+ 2 rows in set (0.00 sec) -- 10、默认情况下,不区分大小写,修改成大小写敏感 -- alter database db2019 character set=utf8; alter database db2019 character set=utf8 collate=utf8_bin; -- alter table tbl_test convert to character set utf8 ; alter table tbl_test convert to character set utf8 collate utf8_bin; -- 只修改这个即可实现区分大小写 -- alter table tbl_test change name name varchar(20) character set utf8 collate utf8_general_ci not null; -- alter table tbl_test modify name varchar(20) character set utf8 collate utf8_general_ci not null; alter table tbl_test change name name varchar(20) character set utf8 collate utf8_bin not null; alter table tbl_test modify name varchar(20) character set utf8 collate utf8_bin not null; mysql> alter database db2019 character set=utf8 collate=utf8_bin; Query OK, 1 row affected (0.00 sec) mysql> show create database db2019; +----------+----------------------------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------------------------+ | db2019 | CREATE DATABASE `db2019` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_bin */ | +----------+----------------------------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> select * from tbl_test where name='aaa'; +----+------+ | id | name | +----+------+ | 1 | aaa | | 3 | AAA | +----+------+ 2 rows in set (0.00 sec) -- 此时只修改库级别的还不行，仍然还需要修改表级别的 mysql> alter table tbl_test convert to character set utf8 collate utf8_bin; Query OK, 4 rows affected (0.08 sec) Records: 4 Duplicates: 0 Warnings: 0 mysql> select * from tbl_test where name='aaa'; +----+------+ | id | name | +----+------+ | 1 | aaa | +----+------+ 1 row in set (0.00 sec)