通过如下sql语句
SELECT col_description(a.attrelid,a.attnum) as comment,format_type(a.atttypid,a.atttypmod) as type,
a.attname as name, a.attnotnull as notnull
FROM pg_class as c,pg_attribute as a
where c.relname ='tablename'and a.attrelid = c.oid and a.attnum>0