lc_ctype

• 15
• 14
• 13
• 12
• 11
• 10
• 9.6
• 9.5
• 9.4
• 9.3
• 9.2
• 9.1
• 9.0
• 8.4
• 8.3
• 8.2

通常 lc_ctype 将与 lc_collate 相同

postgres=# SELECT name, setting
             FROM pg_settings
            WHERE name IN('lc_ctype', 'lc_collate');
    name    |   setting
------------+-------------
 lc_ctype   | en_GB.UTF-8
 lc_collate | en_GB.UTF-8
(2 rows)

创建数据库时设置 lc_ctype 的不同值

postgres=# CREATE DATABASE collation_test
                  TEMPLATE 'template0'
                  LC_CTYPE 'de_DE.UTF8';
CREATE DATABASE

postgres=# \c collation_test
psql (15.3)
You are now connected to database "collation_test" as user "postgres".

collation_test=# SELECT name, setting
             FROM pg_settings
            WHERE name IN('lc_ctype', 'lc_collate');
    name    |   setting
------------+-------------
 lc_ctype   | de_DE.UTF8
 lc_collate | en_GB.UTF-8
(2 rows)

在执行 initdb 时，也可以显式设置 lc_ctype 的集群范围默认值

initdb -D /var/lib/postgres/db-collate/ --lc-ctype=de_DE.UTF8
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with this locale configuration:
  provider:    libc
  LC_COLLATE:  en_GB.UTF-8
  LC_CTYPE:    de_DE.UTF8
  LC_MESSAGES: en_GB.UTF-8
  LC_MONETARY: en_US.UTF-8
  LC_NUMERIC:  en_GB.UTF-8
  LC_TIME:     en_GB.UTF-8
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "german".
...

• PostgreSQL 15 文档： lc_ctype