.. _flatten:

=======
Flatten
=======

Description
-----------
Flatten a nested data structure, generating names for each field by concatenating the field names at each level with a configurable delimiter character. Applies to Struct when schema present, or a Map in the case of schemaless data. The default delimiter is ``.``.

Use the concrete transformation type designed for the record key (``org.apache.kafka.connect.transforms.Flatten$Key``) or value (``org.apache.kafka.connect.transforms.Flatten$Value``).

Properties
----------

.. list-table::
   :header-rows: 1
   :widths: 15 30 10 10 10 10

   *  - Name
      - Description
      - Type
      - Default
      - Valid Values
      - Importance
   *  - ``delimiter``
      - Delimiter to insert between field names from the input record when generating field names for the output record.
      - string
      - `.`
      -
      - medium