EclipseLink中的@ManyToOne映射问题

Question

I'm having trouble with this @ManyToOne map, searched a lot, but still can't find a solution for this problem.

I have these two classes, i will never insert anything into TB_MANUAL, i'll just use it as reference for the CD_MANUAL field in TB_COMPANY, like this:

Company company = new Company();
company.setManual("2"); //Theres already a row with this id in the TB_MANUAL

and then persist company, but i got this error:

Caused By: java.lang.IllegalStateException: During synchronization a new object was found through a relationship that was not marked cascade PERSIST: 2.
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.discoverUnregisteredNewObjects(RepeatableWriteUnitOfWork.java:313)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.calculateChanges(UnitOfWorkImpl.java:723)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1516)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.issueSQLbeforeCompletion(UnitOfWorkImpl.java:3168)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.issueSQLbeforeCompletion(RepeatableWriteUnitOfWork.java:355)
Truncated. see log file for complete stacktrace

-

@Entity
@Table(name = "TB_COMPANY", schema = "ADMPROD")
@Cacheable
public class Company implements Serializable {

private static final long serialVersionUID = 1L;

public Company() {}

public Company(String id) {
    this.id = id;
}

@ManyToOne
@JoinColumn(name = "CD_MANUAL", referencedColumnName = "CD_MANUAL", nullable 
= true)
private Manual manual;


public void setManual(String idManual) {
    this.manual = new Manual(idManual);
}




}

and

@Entity
@Table(name = "TB_MANUAL")
public class Manual implements Serializable{

private static final long serialVersionUID = 1L;

public Manual() {
}

public Manual(String id) {
    this.id = id;
}

@Id
@Column(name = "CD_MANUAL")
private String id;

@Column(name = "DS_OBS_MANUAL")
private String description;

}

Answer 1

You create new Manual every time you set it, so your object is detach from EntityManager, or has not data at all.

I don't argue if that is a good design (althought I've never would do it like that), to over come your problem you should add CascadeType.PERSIST to your relation.

@ManyToOne
@JoinColumn(name = "CD_MANUAL", referencedColumnName = "CD_MANUAL", nullable 
= true, cascade = CascadeType.PERSIST)
private Manual manual;

Answer 2

问题出在Manual表的主键中，JPA找不到ID为1的任何行，因为Manual的主键是char（2），传递“ 1”而不是“ 1”解决了问题。