CREATE COLLATION
7
SQL - Language Statements
CREATE COLLATION
define a new collation
CREATE COLLATION
CREATE COLLATION name (
[ LOCALE = locale, ]
[ LC_COLLATE = lc_collate, ]
[ LC_CTYPE = lc_ctype ]
)
CREATE COLLATION name FROM existing_collation
Description
CREATE COLLATION defines a new collation using
the specified operating system locale settings,
or by copying an existing collation.
To be able to create a collation, you must
have CREATE privilege on the destination schema.
Parameters
name
The name of the collation. The collation name can be
schema-qualified. If it is not, the collation is defined in the
current schema. The collation name must be unique within that
schema. (The system catalogs can contain collations with the
same name for other encodings, but these are ignored if the
database encoding does not match.)
locale
This is a shortcut for setting LC_COLLATE
and LC_CTYPE at once. If you specify this,
you cannot specify either of those parameters.
lc_collate
Use the specified operating system locale for
the LC_COLLATE locale category. The locale
must be applicable to the current database encoding.
(See for the precise
rules.)
lc_ctype
Use the specified operating system locale for
the LC_CTYPE locale category. The locale
must be applicable to the current database encoding.
(See for the precise
rules.)
existing_collation
The name of an existing collation to copy. The new collation
will have the same properties as the existing one, but they
will become independent objects.
Notes
Use DROP COLLATION to remove user-defined collations.
See for more information about collation
support in PostgreSQL.
Examples
To create a collation from the locale fr_FR.utf8
(assuming the current database encoding is UTF8):
CREATE COLLATION french (LOCALE = 'fr_FR.utf8');
To create a collation from an existing collation:
CREATE COLLATION german FROM "de_DE";
This can be convenient to be able to use operating-system-independent
collation names in applications.
Compatibility
There is a CREATE COLLATION statement in the SQL
standard, but it is limited to copying an existing collation. The
syntax to create a new collation is
a PostgreSQL extension.
See Also