TYPO3 Core

Based on the thread "edit mm tables in backend forms with TCA" in the dev list, Ernesto, Franz and I would like to implement a feature described as follows:

In a relational DB system sometimes you have the need for attaching attributes to a record in an MM table.

Example:

tx_books:
uid, title, articles, ...

tx_articles:
uid, title, ...

tx_books_articles_mm:
uid_local (books), uid_foreign (articles), sorting (required), page_number (normal attribute)

In this example the page number (or any other desired information) is stored in the MM relation as it belongs to a specific book / article combo.

In order to get this done, the TCA should get another option like "MM_With_Attributes" that will provide the information neccessary for the described MM table.

Concerning the backend form for editing several ideas were described in the dev list thread. For example:

1) Self extending fieldset
When editing a book record you get a palette or sheet that contains a select field (element browser / selector box / whatever) to select the related article as well as all the fields configured in the new TCA option. In this case: the page_number field. After filling in and saving a new empty fieldset will be created (always one more than entries found in the MM table).

2) Extend button
Same as 1) but with a field / button that indicates to render another set of fields after saving / reloading. (see templavoila section container in FCEs).

3) browse_links popup
We only have the typical select for records and in the popup we will have the additional fields that have been configured via TCA.

Additionally some kind of up / down buttons would be needed for sorting.

record-1: <title> [down][up][edit][del]

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Ernesto, Franz, all the others feel free to add information and suggestions to this.

(issue imported from #M2822)