Having an issue to save through Spring Data JPA - spring

Question

I have 2 tables Employee & EmployeeAddress joined by one to many relationship with Foreign key. When i am trying to save the Employee object i am getting the below log in my console. It might be this unidirectional joining is not happening properly.
2019-07-26 16:32:19 - SQL Error: 1048, SQLState: 23000
2019-07-26 16:32:19 - Column 'EMP_ID' cannot be null
Below are POJO Classes: These are mapped with the DB tables.I am facing issues with the Join column.
Can any one please help me on this.
Thanks in advance.

Answer 1

Try using:
#OneToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})

Answer 2

Assuming the issue is with Relationship so please make sure the following is correct
mappedBy is used on the parent Entity and have the same name
reference in Child Entity
use cascade = CascadeType.PERSIST, cascade = CascadeType.ALL or cascade = CascadeType.MERGE (sometime) at Parent Entity
#JoinColumn is used on Child Entity with correct reference column of Parent
Parent.java
#Entity
#Table(name = "parent")
#Getter
#Setter
#AllArgsConstructor
#NoArgsConstructor
#ToString
public class Parent {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int parentId;
private String name;
#OneToMany(mappedBy="parent",fetch=FetchType.LAZY,cascade = CascadeType.PERSIST)
private List<Child> child = new ArrayList<Child>();
}
Child.java
#Entity
#Table(name = "child")
#Getter
#Setter
#AllArgsConstructor
#NoArgsConstructor
#ToString
public class Child {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int childId;
private String account;
#ManyToOne(fetch = FetchType.LAZY, targetEntity = Parent.class)
#JoinColumn(name="parentId", referencedColumnName = "parentId", nullable = false)
private Parent parent;
}
Controller
#RestController
public class RelationshipController {
#Autowired ParentRepository parentRepository;
#Autowired ChildRepository childRepository;
//save Child with Parent at same
#PostMapping(value = "/onetomany")
public String OneToMany(#RequestBody Parent parent)
{
for (Child child : parent.getChild()) {
child.setParent(parent);
}
parent.setChild(parent.getChild());
parentRepository.save(parent);
return "saved";
/*{
"name":"Romil",
"child":[
{"account":"1"},
{"account":"2"}
]
}*/
}
//save Child with Parent's ID
#PostMapping(value = "/onetomanyPID")
public String OneToMany(#RequestBody Child child)
{
child.setParent(child.getParent());;
childRepository.save(child);
return "saved";
/*{
"account":"3",
"parent":{
"parentId":"1",
"name":"Romil"
}
}*/
}
}