ABSENT KEYSSometimes a key does not exist at all. When using ksLookup() you will get a null pointer. In the C++ Binding the null pointer is wrapped in a key. Thus this is also sometimes called NULL KEYS.
NULL VALUESNull values are binary values without content. They are the only keys that have the size 0.
Null values are always binary values.
EMPTY VALUESEmpty values point to a string that only contains a null byte.
Empty values are possible for both string and binary values.