Hello Georg,
So Zuordnung acts like a kind of M:M link between Filme and Personen.
Let's start with writing a query in the SQL Editor.
If there are 5 FKs then there should be 5 joins (you have NULLs in the FK, so it must be LEFT JOIN).
I created a similar database structure films-assignments-persons
Note, "person" in each join must have an alias to get the "name" field from each join.
SELECT
`a`.`film_number`,
`dir`.`name`as`Director`,
`scr`.`name`AS`Script`,
`cam`.`name`AS`Cameraman`,
`act`.`name`AS`Actor`
FROM
`assignments` `a`
LEFT JOIN `persons` `dir`
ON `a`.`director` = `dir`.`person_id`
LEFT JOIN `persons` `cam`
ON `a`.`cameraman` = `cam`.`person_id`
LEFT JOIN `persons` `scr`
ON `a`.`script` = `scr`.`person_id`
LEFT JOIN `persons` `act`
ON `a`.`director` = `act`.`person_id`
WHERE `film_number` = 1
Now we can add this query on the project tab, replacing "film_number" value with the parameter name.
I added a screenshot for each step:
1. Create pFilmID parameter
2. Write a query
3. Add TableView to the form
4. Map pFilmID parameter to the film_id field of the main form
5. Execute form