Available since: 2.0.0
Time complexity: O(1)
ACL categories:
@write
@hash
@fast
Sets field
in the hash stored at key
to value
, only if field
does not
yet exist.
If key
does not exist, a new key holding a hash is created.
If field
already exists, this operation has no effect.
Integer reply, specifically:
1
if field
is a new field in the hash and value
was set.0
if field
already exists in the hash and no operation was performed.