Hibernate无法添加或更新子行:外键约束失败

问题描述

当我尝试将对象保存到数据库时出现错误:

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)

第一件事是我在Smartphone类中的引用列名称错误，但是我检查了一下，看起来不错.也许有人知道这个问题的原因是什么?

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?

简短的数据库屏幕截图

Short database screenshot

用于创建智能手机表的SQL脚本

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类，但是具有一个关系对象.

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;
    }
}

@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";
    }

解决方案类:

@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;
    }
}

推荐答案

差不多.您必须为Resolution类和下面的类似代码添加上述getId()方法.调用保存方法后，resolution对象的id始终为0.

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)

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