CREATE CONVERSION
CREATE CONVERSION
7
SQL - Language Statements
CREATE CONVERSION
define a new encoding conversion
CREATE [ DEFAULT ] CONVERSION name
FOR source_encoding TO dest_encoding FROM function_name
Description
CREATE CONVERSION defines a new conversion between
character set encodings. Also, conversions that
are marked DEFAULT can be used for automatic encoding
conversion between
client and server. For this purpose, two conversions, from encoding A to
B and from encoding B to A, must be defined.
To be able to create a conversion, you must have EXECUTE privilege
on the function and CREATE privilege on the destination schema.
Parameters
DEFAULT
The DEFAULT clause indicates that this conversion
is the default for this particular source to destination
encoding. There should be only one default encoding in a schema
for the encoding pair.
name
The name of the conversion. The conversion name can be
schema-qualified. If it is not, the conversion is defined in the
current schema. The conversion name must be unique within a
schema.
source_encoding
The source encoding name.
dest_encoding
The destination encoding name.
function_name
The function used to perform the conversion. The function name can
be schema-qualified. If it is not, the function will be looked
up in the path.
The function must have the following signature:
conv_proc(
integer, -- source encoding ID
integer, -- destination encoding ID
cstring, -- source string (null terminated C string)
internal, -- destination (fill with a null terminated C string)
integer -- source string length
) RETURNS void;
Notes
Use DROP CONVERSION to remove user-defined conversions.
The privileges required to create a conversion might be changed in a future
release.
Examples
To create a conversion from encoding UTF8 to
LATIN1 using myfunc:
CREATE CONVERSION myconv FOR 'UTF8' TO 'LATIN1' FROM myfunc;
Compatibility
CREATE CONVERSION
is a PostgreSQL extension.
There is no CREATE CONVERSION
statement in the SQL standard, but a CREATE TRANSLATION
statement that is very similar in purpose and syntax.
See Also