Hi all. I'm playing with pl/python AND i'm with a doubt.
I wanna create a domain to roman numerals.
I have made:
CREATE OR REPLACE FUNCTION valid_roman(text)
RETURNS BOOLEAN
IMMUTABLE
LANGUAGE plpythonu AS
$$
from roman9 import fromRoman
roman = args[0]
try: r = fromRoman(roman) return 'true'
except: return 'false'
$$;
CREATE DOMAIN romano AS text CHECK (valid_roman(VALUE)) ;
CREATE OR REPLACE FUNCTION to_roman(integer)
RETURNS romano
IMMUTABLE
LANGUAGE plpythonu AS
$$
from roman9 import toRoman
number = args[0]
try: r = toRoman(number) return r
except: return 'false'
$$;
CREATE CAST (integer AS romano) WITH FUNCTION to_roman(integer);
And that works:
SELECT to_roman(50)
SELECT to_roman(100)
SELECT valid_roman('XX')
SELECT valid_roman('XXX')
SELECT valid_roman('XXXX')
But my cast doen't works:
SELECT 5::romano
ERROR: value for domain romano violates check constraint "romano_check"
What's wrong?
[]'s
- Walter