This command fetches the full content of all fields and all values of the hash that is associated with the given
keydoes not exist, and empty list is returned.
keyis associated with non-hash data, an error is raised.
Returns list of fields and values.
$ HSET yugahash area1 "Africa"
$ HSET yugahash area2 "America"
$ HGETALL yugahash
1) area1 2) "Africa" 3) area2 4) "America"