– check if a column exists
CREATE OR REPLACE FUNCTION column_exists(colname text, tablename text)
RETURNS boolean AS
$BODY$
DECLARE

q text;
onerow record;

BEGIN
q = ‘SELECT attname FROM pg_attribute WHERE attrelid = ( SELECT oid FROM pg_class WHERE relname = ”’||tablename||”’) AND attname = ”’||colname||”’ ‘;
FOR onerow IN EXECUTE q
LOOP
RETURN true;
END LOOP;
RETURN false;
END;
$BODY$
LANGUAGE ‘plpgsql’ VOLATILE