TYPO3 v15 dev-main snapshot ()

Documentation/Changelog/11.4/Feature-95061-AutoCreationOfMMTablesFromTCA.rst

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+.. include:: /Includes.rst.txt
+
+.. _feature-95061:
+
+=====================================================
+Feature: #95061 - Auto creation of MM tables from TCA
+=====================================================
+
+See :issue:`95061`
+
+Description
+===========
+
+TCA table column fields that define :php:`['config']['MM']` can omit specification of the
+intermediate mm table layout in :file:`ext_tables.sql`. The TYPO3 database analyzer
+takes care of proper schema definition.
+
+This feature has been implemented to simplify developers life and to enable the TYPO3
+core to handle those schema details since many extensions tend to specify incomplete
+or broken mm table schema definitions when dealing with this complex area.
+
+Extensions are strongly encouraged to drop :file:`ext_tables.sql` :sql:`CREATE TABLE`
+definitions for those intermediate tables referenced by :php:`TCA` table columns. Dropping
+these definitions allows the core to adapt and migrate definitions if needed.
+
+Impact
+======
+
+Extension developers don't need to deal with :file:`ext_tables.sql` definitions of
+"mm" tables anymore. The TYPO3 schema analyzer creates the intermediate schema depending
+on :php:`TCA` field definition. The schema analyzer tries to apply default specifications
+if possible. Single :file:`ext_tables.sql` definitions take precedence, though.
+
+In practice, suppose the "local" side of a mm table is defined as such in TCA:
+
+.. code-block:: php
+
+    ...
+    'columns' => [
+        ...
+        'myField' => [
+            'label' => 'myField',
+            'config' => [
+                'type' => 'group',
+                'foreign_table' => 'tx_myextension_myfield_child',
+                'MM' => 'tx_myextension_myfield_mm',
+            ]
+        ],
+        ...
+    ],
+    ...
+
+Until now, a schema definition similar to this had to be in place in :file:`ext_tables.sql`:
+
+.. code-block:: sql
+
+    CREATE TABLE tx_myextension_myfield_mm (
+        uid_local int(11) DEFAULT '0' NOT NULL,
+        uid_foreign int(11) DEFAULT '0' NOT NULL,
+        sorting int(11) DEFAULT '0' NOT NULL,
+
+        KEY uid_local (uid_local),
+        KEY uid_foreign (uid_foreign)
+    );
+
+This section can and should be dropped. Indicators a schema definition is affected by this:
+
+* A table column TCA config defines :php:`MM` with :php:`type='select'`, :php:`type='group'`
+  or :php:`type='inline'`.
+* The "MM" intermediate table has *no* TCA table definition (!).
+* :file:`ext_tables.sql` specifies a table with fields :sql:`uid_local` and :sql:`uid_foreign`.
+
+The schema analyzer takes care of further possible fields apart from :sql:`uid_local` and
+:sql:`uid_foreign`, like :sql:`sorting`, :sql:`sorting_foreign`, :sql:`tablenames`,
+:sql:`fieldname` and :sql:`uid` if necessary, depending on "local" side of the TCA definition.
+
+In general, in case an extension got that definition right up until now, the schema analyzer
+should not drop or add any additional fields automatically when removing these sections from
+:file:`ext_tables.sql`. Developers are strongly encouraged to drop affected :sql:`CREATE TABLE`
+definitions from :file:`ext_tables.sql` and to verify the install tool schema migrator acts as
+expected. The core takes care of these specifications from now on and may add adaptions or migrations
+to streamline further details in the future.
+
+.. index:: Database, ext:core