Hibernate one-to-many mapping relationship

In the CRM system, a customer has multiple contacts, and a contact corresponds to multiple customers.

Requirements: Save a contact and save a customer

Analysis:
Table relationships

SQL statements

Entity class
More than one contact for a single customer

One customer corresponds to multiple contacts

Why choose the Set method
Set set features: Do not repeat the following 0 for the purpose of not occupying space

Note that when the ToString is not associated with the object to come out, because the Linkman ToString called the customer's ToString so that the cycle of death

mapping files
Multiple contacts for one customer

Because a table's primary key can be used as a foreign key for another table, there is no need to describe which property in the customer corresponds to the foreign key in the Linkman

One customer corresponds to multiple contacts

Hibernate one-to-many mapping relationship