Suppose I have a table Customer with these fields

1. customer_id (PK)
2. customer_name
3. customer_surname

I also have some other tables that container a FK pointing to some customer.. For example Table1 has these fields:

1. table1_id (PK)
2. table1_col1
3. table1_customer_id (FK references customer_id in Customer)

Table2 has these fields:

1. table2_id (PK)
2. table2_col1
3. table2_customer_id (FK references customer_id in Customer)

The list of tables referencing the customers in the Customer table can potentially grow and here is where I struggle with the JPA mapping.

I have an Entity Customer like this:

@Entity
@Table(name = "customers")
public class Customer {
    @Id
    @Column(name = "customer_id")
    private String customerId;
    
    @Column(name = "customer_name")
    private String customerName;
    
    @Column(name = "customer_surname")
    private String customerSurname;
    
    // getters & setters
}

but now I don't know how to map the FKs for the other tables. How I would I map for example the Table1?

@Entity
@Table(name = "table1)
public class Table1 {
    @Id
    @Column(name = "table1_id")
    private Long table1Id;
    
    @Column(name = "table1_col1)
    private String table1Col1;
    
    //private Long table1CustomerId;    how can I make this a FK?
    
    // getters & setters
}

The constraints are that each table (Table1, .., TableN) can have at most one customer, but each customer can be in any of the Table1, .., TableN.

Thank you

CodePudding user response：

Use this:

@ManyToOne(fetch = LAZY)
@JoinColumn(name = "table1_customer_id")
private Customer customer;