Removes the specified fields from the hash stored at
Specified fields that do not exist within this hash are ignored.
key does not exist, it is treated as an empty hash and this command returns
@integer-reply: the number of fields that were removed from the hash, not including specified but non existing fields.
>= 2.4: Accepts multiple
fieldarguments. Redis versions older than 2.4 can only remove a field per call.
To remove multiple fields from a hash in an atomic fashion in earlier versions, use a
HSET myhash field1 "foo" HDEL myhash field1 HDEL myhash field2