Inaccuracy in defining relationships cardinality types for PostgreSQL

[ValeriyWorld]

In the method below, we check if foreign key refers to unique constraint of target table and if so the cardinality is going to be ONE_TO_ZERO_OR_ONE or ONE_TO_EXACTLY_ONE. But foreign key can refer to the column/columns that belongs to the Primary key, in this case it should be ONE_TO_ZERO_OR_ONE or ONE_TO_EXACTLY_ONE too, but in our case it is not taken into account and this cases are going into _TO_MANY.

    @cached_property
    def _is_ref_to_unique(self) -> bool:
        """
        Check if the referenced foreign key refers to unique constraint of target table
        """
        ref_fk_columns = {dsf.name for dsf in self.ref_fk_field_list}
        ref_uc_columns = list(
            chain.from_iterable(uc.column_names for uc in self.unique_constraints)
        )

        return any(cn in ref_uc_columns for cn in ref_fk_columns)

[ValeriyWorld]

Closed with #51