DEL

The DEL command in DiceDB is used to remove one or more keys from the database. If a given key does not exist, it is ignored. This command is fundamental for data management in DiceDB, allowing for the deletion of key-value pairs. The command returns the number of keys that were removed.

Syntax

DEL key [key ...]

Parameters

Parameter	Description	Type	Required
key	The name of the key(s) to be deleted.	String	Yes

Return values

Condition	Return Value
Command is successful	Integer (number of keys successfully deleted)
No keys match the specified pattern	0
Syntax or specified constraints are invalid	error

Behaviour

When the DEL command is executed, DiceDB will attempt to remove the specified keys from the database. The command operates in the following manner:

1. Key Existence Check: For each key specified, DiceDB checks if the key exists in the database.
2. Key Removal: If a key exists, it is removed from the database along with its associated value, regardless of the value’s type.
3. Count Removal: The command keeps a count of how many keys were successfully removed.
4. Ignore Non-existent Keys: If a specified key does not exist, it is simply ignored and does not affect the count of removed keys.
5. Return Count: The total count of removed keys is returned as the result of the command.

Errors

The DEL command is generally robust and straightforward, but there are a few scenarios where errors might occur:

1. Wrong Type of Argument: If the command is provided with an argument that is not a valid key (e.g., a non-string type), DiceDB will raise a syntax error.

   • Error Message: (error) ERR wrong number of arguments for 'del' command

2. No Arguments Provided: If no keys are provided to the DEL command, DiceDB will raise a syntax error.

   • Error Message: (error) ERR wrong number of arguments for 'del' command

Example Usage

Basic Usage

Deleting a single key foo:

127.0.0.1:7379> DEL foo
(integer) 1

Deleting Multiple Keys

Deleting multiple keys foo, bar, and baz:

127.0.0.1:7379> DEL foo bar baz
(integer) 2

In this example, if only foo and bar existed, the command would return 2, indicating that two keys were successfully deleted.

Deleting Non-existent Keys

Attempting to delete a non-existent key:

127.0.0.1:7379> DEL nonexistentkey
(integer) 0

Complex Example

Setting multiple keys and then deleting them:

127.0.0.1:7379> SET key1 "value1"
OK
127.0.0.1:7379> SET key2 "value2"
OK
127.0.0.1:7379> SET key3 "value3"
OK
127.0.0.1:7379> DEL key1 key2 key4
(integer) 2

In this example:

• Three keys are set: key1, key2, and key3.
• The DEL command attempts to delete key1, key2, and key4.
• key1 and key2 are successfully deleted.
• key4 doesn’t exist, so it’s ignored.
• The command returns 2, indicating two keys were deleted.

Error Example

Calling DEL without any arguments:

127.0.0.1:7379> DEL
(error) ERR wrong number of arguments for 'del' command