JSON.FORGET

The JSON.FORGET command in DiceDB is used to delete a specified path from a JSON document stored at a given key. If the path leads to an array element, the element is removed, and the array is reindexed. This is useful for modifying and updating portions of a JSON document.

Syntax

JSON.FORGET key path

Parameters

Parameter	Description	Type	Required
key	The name of the key under which the JSON document is stored.	String	Yes
path	The JSONPath expression specifying the part of the JSON document to delete.	String	Yes

Return values

Condition	Return Value
Command successfully deletes a path	The number of paths deleted (Integer)
Path does not exist	0
Invalid key or path	error

Behaviour

• The command locates the JSON document stored at the specified key.
• It evaluates the provided JSONPath expression to identify the part of the document to be deleted.
• If the specified path exists, the targeted part is deleted.
• If the path leads to an array element, the element is removed, and the array is reindexed.
• The command returns the number of paths that were successfully deleted.

Errors

1. Wrong number of arguments:

   • Error Message: (error) ERR wrong number of arguments for 'JSON.FORGET' command
   • Occurs when the command is called with an incorrect number of arguments.

2. Key does not exist:

   • Error Message: (error) ERR key does not exist
   • Occurs if the specified key is not present in the database.

3. Invalid JSONPath expression:

   • Error Message: (error) ERR invalid path
   • Occurs when the provided JSONPath expression is invalid or malformed.

4. Path does not exist:

   • Error Message: (error) ERR path does not exist
   • Occurs if the specified path does not exist within the JSON document.

Example Usage

Basic Usage

Deleting the age field from a JSON document stored at key user:1001:

127.0.0.1:7379> JSON.FORGET user:1001 $.age
(integer) 1

Deleting an Element from a JSON Array

Deleting the second element ("swimming") from the hobbies array in the JSON document stored at key user:1002:

127.0.0.1:7379> JSON.FORGET user:1002 $.hobbies[1]
(integer) 1

updated document:

{
  "name": "Jane Doe",
  "hobbies": ["reading", "hiking"]
}

Deleting a Non-Existent Path

Attempting to delete a non-existent path in the document at key user:1001:

127.0.0.1:7379> JSON.FORGET user:1001 $.nonexistent
(integer) 0