SETNX

Syntax

1. SETNX key value

Time complexity: O(1)

ACL categories: @write, @string, @fast

Set key to hold string value if key does not exist. When key already holds a value, no operation is performed. SETNX is short for “SET if Not eXists”.

Return

Integer reply, specifically:

• 1 if the key was set
• 0 if the key was not set

Examples

1. dragonfly> SETNX mykey "Hello"
2. (integer) 1
3. dragonfly> SETNX mykey "World"
4. (integer) 0
5. dragonfly> GET mykey
6. "Hello"