3.13. Collations

Collations are objects which allow specifying the sorting mode and character classification behavior either per column or operation. Collations can be used to override the way data is sorted in a database even if this one has its own mode defined by LC_COLLATE and LC_CTYPE attributes.

Attribute Description
Collation This field can be used to create a new object from an existing collation.
Locale This is a shortcut to specify the attributes LC_COLLATE and LC_CTYPE.
Encoding Charset in which the collation works.
LC_COLLATE Specify in which language the string sorting must be applied.
LC_CTYPE Specify in which language the character categorization (upper, lower and digit) must be applied.

Note: the attributes Collation, Locale, LC_COLLATE and LC_CTYPE are mutually exclusive, thus you can't use all of them at once.

** Collation DDL **

https://www.postgresql.org/docs/current/static/sql-createcollation.html

Jan 3, 2020 at 12:33