Unique constraint in pivot table

[jeroni]

I have a question regarding pivot tables. Having this database structure as example:

I want to use row_to_invoice and row_to_budget as pivot tables. In both tables row_id is unique, the correct way to define a pivot table in, for example, invoice entity should be:

// Invoice entity
@ManyToMany({ entity: () => 'Row', pivotTable: 'row_to_invoice', joinColumn: 'invoice_id', inverseJoinColumn: 'row_id', cascade: [Cascade.REMOVE] })
rows: Collection<Row> = new Collection<Row>(this);

My question is if there's a way to define the non-owning side as entities and not collections, similar to @OneToOne pattern in the row entity as row_id in both pivot tables is unique:

// Row entity
@Somehow()
invoice: Invoice;

@Somehow()
budget: Budget;