.. include:: ../../Includes.txt


.. _administration-mm:

MM-relations configuration
^^^^^^^^^^^^^^^^^^^^^^^^^^

Things get a bit more complicated with MM-relations, where additional
configuration is required. The related properties are described below.

.. tip::

   If all this seems a bit confusing, please refer to the
   :ref:`chapter about mapping MM relations <user-mapping-data-mm>`.
   Hopefully it will help (this is not a simple topic).


.. _administration-mm-properties:

Properties
""""""""""

.. container:: ts-properties

   ========================= =====================================================
   Property                  Data type
   ========================= =====================================================
   additionalFields_         array
   mapping_                  :ref:`Mapping configuration <administration-mapping>`
   multiple_                 boolean
   sorting_                  string
   ========================= =====================================================


.. _administration-mm-properties-mapping:

mapping
~~~~~~~

Type
  :ref:`Mapping configuration <administration-mapping>`

Description
  This is similar to the :ref:`mapping property <administration-columns-properties-mapping>`
  for columns. It is used to define which table to link to and
  which column in that table contains the external primary key.

Scope
  Store data


.. _administration-mm-properties-additional-fields:

additionalFields
~~~~~~~~~~~~~~~~

Type
  array

Description
  List of fields that must be stored along the local and foreign keys in
  the MM table. For each such field, define which TYPO3 CMS MM-table field
  corresponds to which external data field.

Scope
  Store data


.. _administration-mm-properties-multiple:

multiple
~~~~~~~~

Type
  boolean

Description
  If some MM-relations exist several times in your external data
  (because they have various additional fields), you must set this
  property to 1, so that they are preserved (otherwise TCEmain will take
  only unique "uid\_local"-"uid\_foreign" pairs into account).

Scope
  Store data


.. _administration-mm-properties-sorting:

sorting
~~~~~~~

Type
  string

Description
  Indicates that the data is to be sorted according to that particular
  field from the external data.

  Note that since the external import relies on TCEmain to store the
  data, TCEmain sets its own numbering for sorting, thus the value in
  sorting is never used as is, but just for ordering the records. So if
  the records in the external source are already sorted, there's no need
  to define the "sorting" property.

Scope
  Store data


.. _administration-mm-notes:

Additional notes
""""""""""""""""

When the :ref:`additionalFields <administration-mm-properties-additional-fields>`
and/or :ref:`multiple <administration-mm-properties-multiple>`
properties are used, additional database operations are performed to honour these
settings, as it is not traditional behaviour for TYPO3 MM-relations.
It should be possible with IRRE, but this isn't supported yet.

Also note that these extra operations assume that the MM-relation
is defined as originating **from** the currently imported table.
This means that if you are importing table "foo" and its relations
to table "bar", the import script assumes that the foreign keys of
table "foo" are going into the :code:`uid_local` column. Importing
from the "other" side is not supported yet.


.. _administration-mm-example:

Example
"""""""

This example shows how the "employee" field of the external data
is mapped to the "fe_users" table to consitute the list of members
in a team.

.. code-block:: php

	'members' => array(
		'exclude' => 0,
		'label' => 'LLL:EXT:externalimport_tut/locallang_db.xml:tx_externalimporttut_teams.members',
		'config' => array(
			'type' => 'group',
			'size' => 5,
			'internal_type' => 'db',
			'allowed' => 'fe_users',
			'MM' => 'tx_externalimporttut_teams_feusers_mm',
			'maxitems' => 100
		),
		'external' => array(
			0 => array(
				'field' => 'employee',
				'MM' => array(
					'mapping' => array(
						'table' => 'fe_users',
						'referenceField' => 'tx_externalimporttut_code',
						'default' => ''
					),
					'sorting' => 'rank'
				)
			)
		)
	),