How can i get entity mapping without infinite recursion?

Question

I have three tables and three entity classes.

CREATE TABLE public.users (
    id bigserial NOT NULL,
    email_address varchar(255) NOT NULL,
    password varchar(100) NOT NULL,
    "name" varchar(50) NOT NULL,
    phone_number varchar(15) NOT NULL,
    status int2 NULL DEFAULT 1,
    created_time timestamp(0) NULL DEFAULT now(),
    updated_time timestamp(0) NULL,
    image bytea NULL,
    user_type int2 NULL DEFAULT 0,
    CONSTRAINT users_pk PRIMARY KEY (id),
    CONSTRAINT users_un UNIQUE (email_address)
);

CREATE TABLE public.modules (
    id bigserial NOT NULL,
    "name" varchar(100) NOT NULL,
    description varchar(2000) NULL,
    status int2 NULL,
    CONSTRAINT modules_pk PRIMARY KEY (id),
    CONSTRAINT modules_un UNIQUE (name)
);

CREATE TABLE public.module_user_mapper (
    id bigserial NOT NULL,
    user_id int8 NOT NULL,
    module_id int8 NOT NULL,
    CONSTRAINT module_user_mapper_pk PRIMARY KEY (id)
);
ALTER TABLE public.module_user_mapper ADD CONSTRAINT modules_module_id_fkey FOREIGN KEY (module_id) REFERENCES modules(id);
ALTER TABLE public.module_user_mapper ADD CONSTRAINT modules_user_id_fkey FOREIGN KEY (user_id) REFERENCES users(id);

Entity Class

@Entity
@Table(name = "users")
@Data
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
public class Users implements Serializable 
{
    private static final long serialVersionUID = 1L;
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Long id;
    
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 255)
    @Column(name = "email_address")
    private String emailAddress;
    
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 100)
    @Column(name = "password")
    private String password;
    
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 50)
    @Column(name = "name")
    private String name;
    
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 15)
    @Column(name = "phone_number")
    private String phoneNumber;
    
    @Column(name = "status")
    private Short status;
    @Column(name = "created_time")
    @Temporal(TemporalType.TIMESTAMP)
    private Date createdTime;
    
    @Column(name = "updated_time")
    @Temporal(TemporalType.TIMESTAMP)
    private Date updatedTime;
    
    @Column(name = "image")
    private byte[] image;
    @Column(name = "user_type")
    private Short userType;
    
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "userId")
    private Collection<ModuleUserMapper> moduleUserMapperCollection;
}

@Entity
@Table(name = "modules")
@Data
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
public class Modules implements Serializable {

    private static final long serialVersionUID = 1L;
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Long id;
    
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 100)
    @Column(name = "name")
    private String name;
    
    @Size(max = 2000)
    @Column(name = "description")
    private String description;
    
    @Column(name = "status")
    private Short status;
    
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "moduleId")
    private Collection<ModuleUserMapper> moduleUserMapperCollection;
}

@Entity
@Table(name = "module_user_mapper")
@Data
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
public class ModuleUserMapper implements Serializable {

    private static final long serialVersionUID = 1L;
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Long id;
    
    @JoinColumn(name = "module_id", referencedColumnName = "id")
    @ManyToOne(optional = false)
    private Modules moduleId;
    
    @JoinColumn(name = "user_id", referencedColumnName = "id")
    @ManyToOne(optional = false)
    private Users userId;
}

When i access get all users - i need all users and their modules without infinite recursion. when i access get all modules - i need all modules & its users without infinite recursion.

currently i am trying to access get all users - getting all users and their modules with infinite recursion. I tried with @JsonIgnore, but i remove the child entity.

I am using SpringBoot version 2.1.6.RELEASE & spring boot JPA

infinite recursion means - get all users = User -> Module -> User -> Modules etc.

If any wrong in my entity mapping or table creation, please help me?

What do you mean by "looping"? It sounds like you're looking for eager fetching strategy. — Sorin, Mar 11 '21 at 17:00
I think you're trying to say is something about N+1 issue: https://stackoverflow.com/questions/32453989/what-is-the-solution-for-the-n1-issue-in-jpa-and-hibernate — Johnnes Souza, Mar 11 '21 at 17:22

score 0 · Answer 1 · answered Mar 11 '21 at 17:44

Looking at your code example, it seems to me that you're actually trying to emulate a Many-to-Many Relationship between your Module and User Entity. If that's the case, maybe this will answer your question?

hibernate @ManyToMany bidirectional eager fetching

How can i get entity mapping without infinite recursion?

Entity Class

1 Answers1