Java 错误：无法添加或更新子行：外键约束在使用 mysql 的休眠中失败
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时间：2020-08-13 04:55:15 来源:igfitidea点击:
ERROR: Cannot add or update a child row: a foreign key constraint fails in hibernate using mysql
提问by Fahdie
i need help in one to many mapping with FROM INDEX.Java and many to one mapping from the requirement.
我需要使用 FROM INDEX.Java 进行一对多映射以及从需求进行多对一映射方面的帮助。
I get the following error when i run my demo.java
运行 demo.java 时出现以下错误
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
Jan 01, 2014 11:55:49 PM org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService
INFO: HHH000399: Using default transaction strategy (direct JDBC transactions)
Jan 01, 2014 11:55:49 PM org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init>
INFO: HHH000397: Using ASTQueryTranslatorFactory
Hibernate: select max(pid) from project
Hibernate: insert into project (deadline, email, pname, password, pid) values (?, ?, ?, ?, ?)
Hibernate: insert into requirement (ar, fr, nfr, description, pid, rname, rid) values (?, ?, ?, ?, ?, ?, ?)
Jan 01, 2014 11:55:50 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 1452, SQLState: 23000
Jan 01, 2014 11:55:50 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: Cannot add or update a child row: a foreign key constraint fails (`proj`.`requirement`, CONSTRAINT `requirement_ibfk_1` FOREIGN KEY (`pid`) REFERENCES `project` (`pid`))
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`proj`.`requirement`, CONSTRAINT `requirement_ibfk_1` FOREIGN KEY (`pid`) REFERENCES `project` (`pid`))
this is the error log that i get
这是我得到的错误日志
package proj;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import org.hibernate.annotations.Cascade;
import org.hibernate.annotations.GenericGenerator;
@Entity @Table(name="project")
public class Index {
int pid;
String name;
String email;
String password;
String deadline;
private transient List<Requirment> Requirment;
public Index() {
// TODO Auto-generated constructor stub
}
public void setName(String name) {
this.name = name;
}
public void setPid(int pid) {
this.pid = pid;
}
public void setEmail(String email) {
this.email = email;
}
public void setPassword(String password) {
this.password = password;
}
public void setDeadline(String deadline) {
this.deadline = deadline;
}
public void setRequirment(List<Requirment> requirment) {
Requirment = requirment;
}
/////////////////////////////////////////////
@Column (name="pname")
public String getName() {
return name;
}
@Id
@GeneratedValue(generator="increment")
@GenericGenerator(name="increment", strategy = "increment")
@Column(name = "pid")
public int getPid() {
return pid;
}
@Column (name="deadline")
public String getDeadline() {
return deadline;
}
@Column (name="email")
public String getEmail() {
return email;
}
@Column (name="password")
public String getPassword() {
return password;
}
@OneToMany(fetch=FetchType.EAGER, mappedBy="ind")
//@Cascade({org.hibernate.annotations.CascadeType.ALL})
public List<Requirment> getRequirment() {
return Requirment;
}
}
THIS IS THE INDEX.JAVA
这是索引.JAVA
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import org.hibernate.annotations.Cascade;
import org.hibernate.annotations.GenericGenerator;
@Entity @Table(name="requirement")
public class Requirment {
int pid;
int rid;
String rname;
String desp;
boolean FR;
boolean NFR;
boolean AR;
private transient Index ind;
public void setAR(boolean aR) {
AR = aR;
}
public void setDesp(String desp) {
this.desp = desp;
}
public void setFR(boolean fR) {
FR = fR;
}
public void setNFR(boolean nFR) {
NFR = nFR;
}
public void setPid(int pid) {
this.pid = pid;
}
public void setRid(int rid) {
this.rid = rid;
}
public void setRname(String rname) {
this.rname = rname;
}
public void setInd(Index ind) {
this.ind = ind;
}
public Requirment() {
// TODO Auto-generated constructor stub
}
@Column (name="description")
public String getDesp() {
return desp;
}
@Column (name="pid")
public int getPid() {
return pid;
}
@Column (name="rname")
public String getRname() {
return rname;
}
@Id
@Column (name="rid")
public int getRid() {
return rid;
}
@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name="pid", nullable=false, insertable=false, updatable=false)
public Index getInd() {
return ind;
}
@Column (name="fr")
public boolean getFR() {
return this.FR;
}
@Column (name="ar")
public boolean getAR() {
return this.AR;
}
@Column (name="nfr")
public boolean getNFR() {
return this.NFR;
}
}
THIS IS REQUIREMENT.JAVA
这是要求.JAVA
public class demo {
public static void main(String[] args)
{
Index temp=new Index();
//temp.setPid(9);
temp.setName("SRE");
temp.setEmail("[email protected]");
temp.setPassword("1234");
temp.setDeadline("20/12/13");
//DataAccessUtil.del(Index.class, 1);
Requirment req=new Requirment();
req.setInd(temp);
req.setPid(temp.pid);
req.setAR(false);
req.setNFR(false);
req.setFR(true);
req.setRname("testing");
req.setDesp("testing phase at night");
req.setRid(1);
DataAccessUtil.save(temp);
//temp.getRequirment().add(req);
DataAccessUtil.save(req);
}
}
this is demo.java
这是 demo.java
create database project;
use project;
create table project( pid int(4) PRIMARY KEY, password varchar(50) , pname varchar(50), email varchar(50) , deadline varchar(50));
create table requirement( pid int(4) NOT NULL, rid int(4), rname text, description text, fr
tinyint(1), nfr tinyint(1), ar tinyint(1), FOREIGN KEY (pid) REFERENCES project(pid)
ON DELETE CASCADE );
THIS IS SQL SCRIPT
这是 SQL 脚本
采纳答案by oceansize
How can it work if you declared the Requirement.ind @ManyToOne association with insertable=false, updatable=false?
That essentially means it's read only.
如果您声明 Requirement.ind @ManyToOne 关联，它如何工作insertable=false, updatable=false？这基本上意味着它是只读的。
I see the pidprimitive for that column also but in your example you're setting req.setPid(temp.pid)before tempis actually saved.
So it doesn't make any sense.
我也看到了该列的pid原语，但在您的示例中，您是req.setPid(temp.pid)在实际保存temp之前进行设置的。所以没有任何意义。
You can have the following solutions:
您可以有以下解决方案：
- Remove
insertable=false, updatable=falsefrom the Requirement.ind @ManyToOne association. Remove the Requirement.pid property cause it seems that it doesn't make any sense at all (you can always use Requirement.ind.getPid). - Use the
req.setPid(temp.pid);but after temp is saved(i.e. temp.pid is assigned)
insertable=false, updatable=false从 Requirement.ind @ManyToOne 关联中删除。删除 Requirement.pid 属性，因为它似乎根本没有任何意义（您始终可以使用 Requirement.ind.getPid）。- 使用
req.setPid(temp.pid);但在临时保存后（即分配了 temp.pid）
回答by Mani
In Index bean, where the many to oneassociation is given use is as
在索引 bean 中，many to one使用关联的地方是
@ManyToOne(fetch=FetchType.EAGER,cascade = CascadeType.ALL)
