If you are naming your foreign key fields consistently for example extras.products_id -> products.id or using some fairly unique data type like GUID for your keys it could be intelligently inferred.
If you’re allowed to query the data you could use the column name/data type to come up with lots of good candidates, and then if then verify by checking whether the actual values correspond (assuming that it’s something like a uuid or username column and not a serial/int column)
Newbie here. How do you express foreign key - primary key relationships when you define your schema, in Postgresql and/or SQLServer ? Is it via an integrity constraint, or can it be just an informative metadata ?
No AI magic can know the foreign keys from the schema alone and even with data the results would be uncertain.