Question

当我试图将对象保存到数据库时，我收到错误：

configuration.yaml

首先，我在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)类中的引用列名称错误，但我检查了它，看起来很好。也许有人弄清楚这个问题的原因是什么？

短数据库截图

用于创建智能手机表的SQL脚本

Smartphone

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)类，但有一个关系对象。

Smartphone

[编辑：解析智能手机型号并保存到数据库]

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;
    }
}

[编辑：已添加]分辨率等级：

@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";
    }

Answer 1

根据add/update中存储的值，您尝试将resolution行id设置为smartphone字段的有效值。
您必须先将行插入resolution表。

Answer 2

差不多好。您必须为getId()类和以下类似代码添加上述Resolution方法。保存方法调用后，您的resolution对象可能始终为id。

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

Hibernate无法添加或更新子行：外键约束失败

2 个答案: