Example of One To Many relation in spring boot
In this example two entities are created, User and Post, a user can create many posts so a OneToMany relationship is established
To achieve this, the posts attribute is defined in the user entity as follows
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="user_id", referencedColumnName="user_id")
private List<Post> posts;
And in the Post entity, the attribute by which the two entities will be linked is defined
@Column(name="user_id")
private Integer userId;
This allows us to automatically create new posts from the user entity administration
User user1 = new User();
Post post1 = new Post();
post1.setBody("Este es un día hermoso");
Post post2 = new Post();
post2.setBody("Esta es una noche espléndida");
user1.setName("Pepe");
user1.setPosts(Arrays.asList(post1,post2));
userRepository.save(user1);
Executing the previous code the user Pepe is created and simultaneously two posts are created
