Why can't I link two tables in Open Office Base?

Question

Database

Created two tables ("Cars" and "Stores"):
Here are "Cars":

Here are "Stores":

I can't connect these tables with the "Shop" fields, the following error appears:

And this despite the fact that the primary keys are set to "ID" fields that are filled in automatically and are not repeated in any other table...
How to solve this problem and link these two tables? Thanks in advance.

Answer 1

The "Shop" field in the "Cars" table should not be VARCHAR, but INT, as it should contain only the store ID.