Ekiras

Also Read One To One Mapping Let's create two entities/domains Employee and Department such that they have the following relation between them. Department has-many Employees which means an Employee can belong to only one Department and a Department can have many Employee and Department is the owner of the relation between the two. Owner of the relation means that Owner can exist without the dependent entity but dependent entity cannot stay without the owner entity . Dependent Entity of Relationship will containes the 'foreign key' ID of the Owner entity . In this case, Address will contian the Employee Id in >its table as shown in the table structure below. So a Department can exist without Employee but an Employee cannot be there without a Department. If you on deleting an Employee, the Employee-Department mapping will be removed on deleting a Department, all the employees in the department should be deleted. Employee.java package com.ekiras.domain; import jav...

Points To Remember Suppose we have two domains/ entities  User  and  Role  and we want to create a many to many relationship between them them, then we can do it like following in hibernate. Many to Many relationship between two Entities. User.java Create a User class as following package com.ekiras.domain; import java.util.ArrayList; import java.util.Collection; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.ManyToMany; import javax.persistence.Table; @Entity @Table(name = "user") public class User { @Id @GeneratedValue(strategy=GenerationType.AUTO) @Column(name="id") private Long id; @Column(name="email") private String email; @Column(name="password") private String password; @Column(name="enabled") private boolean enabled; @ManyToM...

Points To Remember There are two ways to create hibernate many to many relational mappings in Hibernate. We will discuss both of them in detail here. First one is to use default hibernate mapping to create and manage these relations. By creating a new domain that will manage these relations for us. Suppose we want to have a simple User and Role mapping where a user can have multiple roles and a role can be assigned to multiple users. Then we can create and manage these relations in the following ways. Strategy 1 : Default Hibernate Mappings You can use this strategy as applied like shown in this article . This will make the hibernate to deal with all the mappings and operations like save , update, fetch etc. Advantage : This will make hibernate responsible for the mapping and operations like save, fetch, update etc. Disadvantage : You will not have control over the mapped relation. You will not be able to query the table it will create for mapping. Strategy 2 : Using Domain to Handle...