[FIXED] Hibernate Cannot add or update a child row: a foreign key constraint fails

Issue

When I'm trying to save object into database I got error:

java.sql.SQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`smartphones`.`smartphone`, CONSTRAINT `fk_smartphone_resolution1` FOREIGN KEY (`resolution_id`) REFERENCES `resolution` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION)

First thing is I have wrong name of references column in Smartphone class but I checked and it looks well. Maybe someone figure out what is the reason of this issue?

Short database screenshot

SQL script to create smartphone table

CREATE TABLE IF NOT EXISTS `smartphones`.`smartphone` (
      `id` INT(11) NOT NULL AUTO_INCREMENT,
      `name` VARCHAR(45) NULL DEFAULT NULL,
      `resolution_id` INT(11) NOT NULL,
               ...other
      PRIMARY KEY (`id`, `resolution_id`),
      UNIQUE INDEX `id_UNIQUE` (`id` ASC),
      INDEX `fk_smartphone_resolution1_idx` (`resolution_id` ASC),
      CONSTRAINT `fk_smartphone_resolution1`
        FOREIGN KEY (`resolution_id`)
        REFERENCES `smartphones`.`resolution` (`id`)
        ON DELETE NO ACTION
        ON UPDATE NO ACTION)

Smartphone class but with one relationship object.

package com.project.model;

import javax.persistence.*;

@Entity
public class Smartphone {
    private int id;
    private String name;
    private Resolution resolutionId;

    @Id
    @Column(name = "id")
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "name")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @ManyToOne(fetch=FetchType.EAGER, cascade=CascadeType.PERSIST)
    @JoinColumn(name = "resolution_id", referencedColumnName = "id", nullable = false)
    public Resolution getResolutionId() {
        return resolutionId;
    }

    public void setResolutionId(Resolution resolutionId) {
        this.resolutionId = resolutionId;
    }
}

[Edit: Parsing smartphone model and saving into database]

@RequestMapping(value = { "apple" }, method = RequestMethod.GET)
    public String parseApple(ModelMap model) {

        try {
            String appleData = Utilities.getResourceAsString(this, "json/apple.json");

            JSONArray array = new JSONArray(appleData);

            Session session = sessionFactory.openSession();
            Transaction transaction = session.beginTransaction();

            for (int i = 0; i < array.length(); i++) {
                Smartphone smartphone = new Smartphone();

                String resolutionValue = array.getJSONObject(i).getString("resolution");
                String resolution_w = resolutionValue.split(" ")[0];
                String resolution_h = resolutionValue.split(" ")[2];
                Resolution resolution = new Resolution();
                resolution.setHeight(Integer.valueOf(resolution_h));
                resolution.setWidth(Integer.valueOf(resolution_w));
                resolution.setTypeId(typeService.findByCode(session, Resolution.serialId));
                session.save(resolution);

                smartphone.setResolutionId(resolution);
                //other

                session.save(smartphone);
                break;
            }
            transaction.commit();
            sessionFactory.close();

        } catch (IOException e) {
            e.printStackTrace();
        }

        return "index";
    }

[Edit: Added] Resolution class:

@Entity
public class Resolution {
    public static final int serialId = 106;

    private int id;
    private Integer height;
    private Integer width;
    private Type typeId;
    private Collection<Smartphone> resolutionId;

    @Id
    @Column(name = "id")
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "height")
    public Integer getHeight() {
        return height;
    }

    public void setHeight(Integer height) {
        this.height = height;
    }

    @Basic
    @Column(name = "width")
    public Integer getWidth() {
        return width;
    }

    public void setWidth(Integer width) {
        this.width = width;
    }

    @ManyToOne(fetch=FetchType.EAGER)
    @JoinColumn(name = "type_id", referencedColumnName = "id", nullable = false)
    public Type getTypeId() {
        return typeId;
    }

    public void setTypeId(Type typeId) {
        this.typeId = typeId;
    }

    @LazyCollection(LazyCollectionOption.FALSE)
    @OneToMany(mappedBy = "resolutionId")
    public Collection<Smartphone> getResolutionId() {
        return resolutionId;
    }

    public void setResolutionId(Collection<Smartphone> resolutionId) {
        this.resolutionId = resolutionId;
    }
}

Solution

Almost well. You have to add above getId() method for Resolution class and similar code below. Probably your resolution object has always 0 as id after save method call.

@Column(name = "id", unique = true, nullable = false)
@GeneratedValue(strategy = GenerationType.AUTO)

Answered By - Michael
Answer Checked By - Terry (JavaFixing Volunteer)