Am I doing this right? PhD student struggling with some implementation..

[Vijon Baraku]

Dears,

I am a student working on a data federation project for which I am trying to use ontop.

I am not using the CLI, or the Protege extension. I am developing a framework where a controller could go ahead and select their Tables and Columns and map specific columns to specific Schema.org Properties. For example, for a users table, they would map column "Tax_id" to class: Schema:Person -> property: TaxId. This generates mapping then generates OBDA files.

Now so far this works fine. If I map the columns to the Person properties I can query just fine any information regarding that person. The problems I am encountering is when for example I have an "Orders" table. This table would have for example "order_date". This column I can map to class: Schema:Orders -> property: oderDate. However, in orders, I have foreign keys of users. Where would I map these? How would I connect that it was in fact the Person with taxid 123 that did this Order? 

Am I missing something? I would be happy to talk to someone with more experience in this than me. I appreciate the help a lot!

[André T.]

Hi, 

Foreign keys typically become object properties (linking entities like a Person to an Order).

<Order_1001> <orderedBy> <Person_123>

Therefore, you need to define an object property mapping. Maybe you find this article helpful:

https://ontopic.ai/en/tech-notes/mapping-many-to-many-relationships/

BR, André

[Vijon Baraku]

Hey thanks a lot Andre for pointing me to the right direction. I will try to fix my implementation based on your feedback.

Cheers again,

Vijon