Null Foreign Key (Springboot, Hibernate, Postman) - spring-boot

Question

I am using Springboot with Hibernate and I would like to save a new “post” using a POST request to my database. One thing that I would like to highlight is that I am using the dependency “spring-boot-starter-data-rest”.
Schema of the database (MySQL):
Class User:
#Entity
#Table(name="user")
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="id", nullable = false)
public int id;
#OneToMany(mappedBy = "user_id_fk")
public Set<Post> posts;
#Column(name="email")
private String email;
#Column(name="username")
private String username;
#Column(name="password")
private String password;
#Column(name="first_name")
private String firstName;
#Column(name="last_name")
private String lastName;
#Column(name="create_time")
protected Date createTime;
#Column(name="type")
private String accountType;
public User() {
this.createTime = new java.util.Date();
}
public User(String email, String username, String password, String firstName, String lastName, Date createTime, String accountType) {
this.email = email;
this.username = username;
this.password = password;
this.firstName = firstName;
this.lastName = lastName;
this.createTime = createTime;
this.accountType = accountType;
this.createTime = new java.util.Date();
}
public User(int id, String email, String username, String password, String firstName, String lastName, Date createTime, String accountType) {
this.id = id;
this.email = email;
this.username = username;
this.password = password;
this.firstName = firstName;
this.lastName = lastName;
this.createTime = createTime;
this.accountType = accountType;
this.createTime = new java.util.Date();
}
Plus the Getters & Setters & toString().
Class Post:
#Entity
#Table(name="post")
public class Post implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="id")
public int id;
#ManyToOne(optional = false)
#JoinColumn(name = "user_id_fk", nullable = false)
public User user_id_fk;
#Column(name="comment")
private String comment;
#Column(name="likes")
private int likes;
#Column(name="dislike")
private int dislike;
#Column(name="create_time")
protected Date createTime;
public Post() {
this.createTime = new java.util.Date();
}
public Post(String comment, int likes, int dislike, User user_id_fk) {
this.user_id_fk = user_id_fk;
this.comment = comment;
this.likes = likes;
this.dislike = dislike;
this.createTime = new java.util.Date();
}
public Post(int id, User user_id_fk, String comment, int likes, int dislike) {
this.id = id;
this.user_id_fk = user_id_fk;
this.comment = comment;
this.likes = likes;
this.dislike = dislike;
this.createTime = new java.util.Date();
}
Plus the Getters & Setters & toString().
Post request (I'm using Postman to send the request):
{
"comment" : "This is a comment",
"likes" : 123,
"dislike" : 1,
"user_id_fk" :
[
{
"id" : 1
}
]
}
In the request at the "user_id_fk" I tried with [ {"id" : 1 } ] and with { "id" : 1 } but the result was the same.
Issue:
When I am executing exactly the same code from my controller everything works are excepted. Bear in mind that I am using the dependency “spring-boot-starter-data-rest”.
Also, when I am executing the code without the “optional = false” and “nullable = false” is inserting the data into the database but the “user_id_fk” is null :(.
The error that I am getting:
not-null property references a null or transient value : com.citizen.citizen.entity.Post.user_id_fk;
nested exception is org.hibernate.PropertyValueException: not-null property references a null or transient value : com.citizen.citizen.entity.Post.user_id_fk]
That means that the foreign key ("user_id_fk") is null but should not be null.
Any help will be greatly appreciated.

Answer 1

I just remove the dependency "spring-boot-starter-data-rest" and I solved the issue by creating my custom rest and everything works. Kisses!

Answer 2

According to this article, you should make user_id_fk nullable and then:
Send POST to create User
Send second POST to create Post
Send PUT to create a relation between the two.
This article states the same.
And the documentation only mentions handling associations via association links.