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DECR

Decrements the integer value of a key by one.

Syntax​

DECR key

Parameters​

  • key: The name of the key whose value you want to decrement.

Details​

  • Available since: 1.0.0
  • Time complexity: O(1)
  • ACL categories: @write, @string, @fast

The DECR command decreases the integer value stored at key by one. If the key does not exist, it is set to 0 before performing the decrement operation. The operation is atomic, ensuring that concurrent requests are correctly handled.

Examples​

Basic Usage​

Assume we have a key called mykey with the value "5":

SET mykey "5"

To decrement the value of mykey by 1:

DECR mykey

This will return:

(integer) 4

The value of mykey will now be "4".

Handling a Non-Existent Key​

If the key does not exist:

DECR newkey

This will return:

(integer) -1

The key newkey is now set to "-1".

Edge Cases​

  • If the key holds a value that is not an integer or cannot be represented as an integer, an error is returned.
  • If the resulting value after the decrement operation is less than the minimum integer value allowed (-2^63), an error is returned.

RESP2/RESP3 Reply​

  • Integer reply: the value of the key after the decrement operation.