Memcached prepend Command

The Memcached prepend command is used to append data to the beginning of an existing key's value.

Syntax:

The basic syntax format for the prepend command is as follows:

prepend key flags exptime bytes [noreply]
value

Parameter descriptions are as follows:

• key: The key in the key-value structure used to find the cached value.

• flags: An integer parameter that the client can use to store additional information about the key-value pair.

• exptime: The duration for which the key-value pair is stored in the cache (in seconds, 0 means forever).

• bytes: The number of bytes stored in the cache.

• noreply (optional): This parameter informs the server that no response is needed.

• value: The stored value (always on the second line) (can be directly understood as the value in the key-value structure).

Example

Here is an example:

• First, we store a key named tutorialpro with a value of memcached in Memcached.

• Then, we retrieve the value using the get command.

• Next, we use the prepend command to append "redis" to the beginning of the value for the key tutorialpro.

• Finally, we retrieve the value again using the get command.

  set tutorialpro 0 900 9
  memcached
  STORED
  get tutorialpro
  VALUE tutorialpro 0 9
  memcached
  END
  prepend tutorialpro 0 900 5
  redis
  STORED
  get tutorialpro
  VALUE tutorialpro 0 14
  redismemcached
  END
  

Output

If the data is added successfully, the output will be:

STORED

Output information descriptions are as follows:

• STORED: Output after successful saving.

• NOT_STORED: The key does not exist in Memcached.

• CLIENT_ERROR: Execution error.