You placed the fetched Whois variables outside the execute function!
Change:
cur.execute("""INSERT INTO wrec (dname, wfull, dns) VALUES (%s, %s, %s)""") , (wi.domain_name, wi.text, wi.name_servers)
To:
cur.execute("""INSERT INTO wrec (dname, wfull, dns) VALUES (%s, %s, %s)""", (wi.domain_name, wi.text, wi.name_servers))
Edit:
And don't forget to add:
db.commit()
at the end of the script.