HGETALL

The HGETALL command in DiceDB is used to retrieve all the fields and values of a hash stored at a specified key. This command is particularly useful when you need to fetch the entire hash in one go, rather than fetching individual fields one by one.

Syntax

HGETALL key

Parameters

Parameter	Description	Type	Required
key	The key of the hash from which you want to retrieve all fields and values.	String	Yes

Return values

Condition	Return Value
The key exists and is a hash	Array of strings
The key does not exist	Empty array

Behaviour

When the HGETALL command is executed:

1. DiceDB checks if the specified key exists.
2. If the key exists and is of type hash, DiceDB retrieves all the fields and their corresponding values.
3. If the key does not exist, DiceDB returns an empty array.
4. If the key exists but is not of type hash, an error is returned.

Errors

The HGETALL command can raise the following 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 the key holds a non-hash data structure.

2. Incorrect Argument Count:

   • Error Message: (error) ERR wrong number of arguments for 'hgetall' command
   • Occurs if the command is not provided with the correct number of arguments (i.e., more than one).

Example Usage

Retrieving all fields and values from an existing hash

127.0.0.1:7379> HSET user:1000 name "John Doe" age "30" country "USA"
(integer) 3
127.0.0.1:7379> HGETALL user:1000
1) "name"
2) "John Doe"
3) "age"
4) "30"
5) "country"
6) "USA"

Retrieving from a non-existing key

127.0.0.1:7379> HGETALL user:2000
(empty array)

Error Example

Key is not a hash

127.0.0.1:7379> SET user:3000 "This is a string"
OK
127.0.0.1:7379> HGETALL user:3000
(error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value

Invalid number of arguments are passed

127.0.0.1:7379> HGETALL user:3000 helloworld
(error) ERROR wrong number of arguments for 'hgetall' command