Java Community | Help. Code. Learn.•2w ago

Doubt in hibernate

so i created these 2 simple entities package src.main.webapp.Entity;

import lombok.Data;
import src.main.webapp.Embeddable.EmployeeName;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "employee")
@Data
public class EmployeeEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Long salary;

    public EmployeeEntity(Long salary, EmployeeName name, List<LaptopEntity> laptops) {
        this.salary = salary;
        this.name = name;
        this.laptops = laptops;

    }
    private EmployeeName name;
    @OneToMany
    private List<LaptopEntity> laptops;
    public EmployeeEntity(){}
    public EmployeeEntity(Long salary, EmployeeName name) {
        this.salary = salary;
        this.name = name;
    }
}

import lombok.Data;
import src.main.webapp.Embeddable.EmployeeName;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "employee")
@Data
public class EmployeeEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Long salary;

    public EmployeeEntity(Long salary, EmployeeName name, List<LaptopEntity> laptops) {
        this.salary = salary;
        this.name = name;
        this.laptops = laptops;

    }
    private EmployeeName name;
    @OneToMany
    private List<LaptopEntity> laptops;
    public EmployeeEntity(){}
    public EmployeeEntity(Long salary, EmployeeName name) {
        this.salary = salary;
        this.name = name;
    }
}

package src.main.webapp.Entity;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "laptop")
@NoArgsConstructor
@ToString
@Data
public class LaptopEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long lid;
    private String lname;
    @ManyToOne
    private EmployeeEntity employee;
    public LaptopEntity(String lname) {
        this.lname = lname;
    }
}

package src.main.webapp.Entity;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "laptop")
@NoArgsConstructor
@ToString
@Data
public class LaptopEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long lid;
    private String lname;
    @ManyToOne
    private EmployeeEntity employee;
    public LaptopEntity(String lname) {
        this.lname = lname;
    }
}

In case i use a third join table i dont have to explicitly mention cascade to all where as if i use a foregin key in the manyToOne table i have to use it. why exactly?

1 Reply

JavaBot•2w ago

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Doubt in hibernate