JPA Mapping issue - spring-boot

Question

I have the following tables
CREATE TABLE APPUSERS (
APPUSERS_ID INT IDENTITY(1,1),
USERNAME VARCHAR(254) NOT NULL,
PASSWORD VARCHAR(100) NOT NULL,
PRIMARY KEY (USERNAME)
);
CREATE TABLE ALL_ROLES (
ROLE_ID INT IDENTITY(1,1),
ROLENAME VARCHAR(100) NOT NULL,
PRIMARY KEY (ROLENAME)
);
CREATE TABLE USER_ROLES(
USER_ROLE_ID INT IDENTITY(1,1),
USERNAME VARCHAR(254) NOT NULL,
CONSTRAINT FK_USERNAME FOREIGN KEY (USERNAME)
REFERENCES APPUSERS (USERNAME),
ROLENAME VARCHAR(100) NOT NULL,
CONSTRAINT FK_ROLENAME FOREIGN KEY (ROLENAME)
REFERENCES ALL_ROLES (ROLENAME),
PRIMARY KEY (username,rolename)
)
I have created the corresponding Entities(See below) and Repositories
#Entity
#Table(name = "appusers")
public class User {
private Long id;
private String username;
private String password;
private String passwordConfirm;
private Set<Role> roles;
#Id
#Column(name="APPUSERS_ID")
#GeneratedValue(strategy = GenerationType.AUTO)
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
#Transient
public String getPasswordConfirm() {
return passwordConfirm;
}
public void setPasswordConfirm(String passwordConfirm) {
this.passwordConfirm = passwordConfirm;
}
#ManyToMany
#JoinTable(name = "USER_ROLES", joinColumns = #JoinColumn(name = "USERNAME"), inverseJoinColumns = #JoinColumn(name = "ROLENAME"))
public Set<Role> getRoles() {
return roles;
}
public void setRoles(Set<Role> roles) {
this.roles = roles;
}
And
#Entity
#Table(name = "USER_ROLES")
public class Role {
private Long id;
#Column(name="USERNAME")
private String name;
private Set<User> users;
#Id
#Column(name="USER_ROLE_ID")
#GeneratedValue(strategy = GenerationType.AUTO)
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#ManyToMany(mappedBy = "roles")
public Set<User> getUsers() {
return users;
}
public void setUsers(Set<User> users) {
this.users = users;
}
}
When I start the application I get the following error
Foreign key (FKrs04la1w0u7vtog85q1hxlse9:user_roles [rolename])) must have same number of columns as the referenced primary key (user_roles [username,rolename])
I am not able to figure what what is the issue here. Any help is greatly appreciated.
I think the table mappings are all correct but not sure why this error is occurring.

Answer 1

There are a couple of issues on your code, let me explain for steps:
Relationship many to many, you need to create an intermediate table in order to do that so you need to fix these following aspects:
User entity
#Id
#Column(name = "APPUSERS_ID")
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#ManyToMany(mappedBy = "users")
private Set<Role> roles;
Role entity
#Id
#Column(name = "USER_ROLE_ID")
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#ManyToMany
#JoinTable(name = "role_user",
joinColumns = { #JoinColumn(name = "role_id") },
inverseJoinColumns = { #JoinColumn(name = "user_id") })
private Set<User> users;
If you want these entities are generated on database by JPA hibernate just put the following property configuration(you just need to create database with name).
spring.jpa.hibernate.ddl-auto=update
Else I leave you here scripts to execute on database.
-- Table: public.appusers
-- DROP TABLE public.appusers;
CREATE TABLE public.appusers
(
appusers_id bigint NOT NULL,
password character varying(255) COLLATE pg_catalog."default",
password_confirm character varying(255) COLLATE pg_catalog."default",
username character varying(255) COLLATE pg_catalog."default",
CONSTRAINT appusers_pkey PRIMARY KEY (appusers_id)
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;
ALTER TABLE public.appusers
OWNER to postgres;
-- Table: public.role_user
-- DROP TABLE public.role_user;
CREATE TABLE public.role_user
(
role_id bigint NOT NULL,
user_id bigint NOT NULL,
CONSTRAINT role_user_pkey PRIMARY KEY (role_id, user_id),
CONSTRAINT fkma2afyyxc0mraogwivmj0klfe FOREIGN KEY (role_id)
REFERENCES public.user_roles (user_role_id) MATCH SIMPLE
ON UPDATE NO ACTION
ON DELETE NO ACTION,
CONSTRAINT fkmhbomge36ygro6rth9negs1ye FOREIGN KEY (user_id)
REFERENCES public.appusers (appusers_id) MATCH SIMPLE
ON UPDATE NO ACTION
ON DELETE NO ACTION
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;
ALTER TABLE public.role_user
OWNER to postgres;
-- Table: public.user_roles
-- DROP TABLE public.user_roles;
CREATE TABLE public.user_roles
(
user_role_id bigint NOT NULL,
username character varying(255) COLLATE pg_catalog."default",
CONSTRAINT user_roles_pkey PRIMARY KEY (user_role_id)
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;
ALTER TABLE public.user_roles
OWNER to postgres;