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DiceDB

HVALS

The HVALS command in DiceDB retrieves all values in a hash stored at a given key. This command allows you to access only the values within a hash, which is helpful for data inspection or retrieval without needing the field names.

Syntax

Terminal window
HVALS key

Parameters

ParameterDescriptionTypeRequired
keyThe name of the key holding a hashStringYes

Return values

ConditionReturn Value
If the key exists and holds a hashArray of values within the hash
If the key does not exist or is emptyEmpty array []

Behaviour

  • The HVALS command retrieves all values stored in the hash at the specified key, without returning the associated field names.
  • If the hash is empty or key does not exist, it returns an empty array [].
  • If key exists but does not contain a hash, an error is returned.

Errors

  1. Non-hash type or wrong data type:

    • Error Message: (error) WRONGTYPE Operation against a key holding the wrong kind of value
    • Occurs if key holds a non-hash data structure, such as a string or list.

  2. Missing required parameter:

    • Error Message: (error) ERR wrong number of arguments for 'HVALS' command
    • Occurs if the key parameter is missing from the command.

Example Usage

Basic Usage

Retrieving all values in the hash stored at key user:1001

Terminal window
127.0.0.1:7379> HVALS user:1001
1) "John Doe"
2) "30"
3) "john@example.com"

Empty hash

If the hash stored at user:1002 exists but has no fields:

Terminal window
127.0.0.1:7379> HVALS user:1002
(nil)

Non-existent key

If the hash user:1003 does not exist:

Terminal window
127.0.0.1:7379> HVALS user:1003
(nil)

Best Practices

  • Use for Values Only: Use HVALS when only the values within a hash are needed without requiring field names, simplifying value extraction.

Alternatives

  • HGETALL: The HGETALL command retrieves all field-value pairs in a hash, providing both names and values.

Notes

  • Ensure key is a hash type to avoid errors when using HVALS.

Using the HVALS command enables efficient access to all values within a hash structure in DiceDB, simplifying data retrieval when field names are unnecessary.