テーブルのカラム名と型名をとってくる。

SELECT
	pg_attribute.attname,
	pg_type.typname,
	pg_attribute.attlen
FROM
	pg_attribute,
	pg_type
WHERE
	pg_attribute.atttypid = pg_type.oid AND
	( pg_attribute.atttypid < 26 OR pg_attribute.atttypid > 29 ) AND
	attrelid IN (
		SELECT
			pg_class.oid
		FROM
			pg_class,
			pg_namespace
		WHERE
			relname='__TABLE_NAME__' AND
			pg_class.relnamespace=pg_namespace.oid AND
			pg_namespace.nspname='__SCHEMA_NAME__'
	);