[英]Cannot add or update a child row: a foreign key constraint fails Hibernate
[英]Hibernate Cannot add or update a child row: a foreign key constraint fails
当我尝试将 object 保存到数据库中时,出现错误:
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)
首先是我在Smartphone
class 中的参考列名称错误,但我检查了一下,它看起来不错。 也许有人弄清楚这个问题的原因是什么?
简短的数据库截图
SQL 脚本创建智能手机表
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 但有一种关系 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;
}
}
[编辑:解析智能手机 model 并保存到数据库]
@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";
}
[编辑:添加] 分辨率 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;
}
}
您正尝试根据smartphone
存储的值将行add/update
为没有id
字段有效值的resolution
。
您必须先将行插入resolution
表。
差不多好。 您必须为Resolution
类和下面的类似代码添加上面的getId()
方法。 可能是你的resolution
对象始终0作为id
保存方法调用之后。
@Column(name = "id", unique = true, nullable = false)
@GeneratedValue(strategy = GenerationType.AUTO)
添加@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
Model class 中的注释。
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