[jboss-user] [EJB 3.0] - Re: Cannot join @OneToOne on non-PK fields?
# @JoinColumn(name="status", referencedColumnName="code")
-----
please read the jpa spec to understand how to use @JoinColumn: you can only use one of
this attributes not both, because if you use both, name="status" is used as
referenced key
# Lazy fetching has no problem, because I also use it:
@javax.persistence.Entity
| public class Customer implements java.io.Serializable{
| /** The serialVersionUID */
| private static final long serialVersionUID = 1L;
| private long id;
| private String lastName;
| private String firstName;
| private Address address;
|
| #1 can be used
| @javax.persistence.OneToOne(cascade={CascadeType.ALL}, fetch=FetchType.LAZY)
| @javax.persistence.JoinColumn(name="ADDRESSID")
|
| #2 can also be used
| @javax.persistence.OneToOne(cascade={CascadeType.ALL}, fetch=FetchType.LAZY)
| @javax.persistence.JoinColumn(referencedColumnName="ZIP")
| public Address getAddress() {return this.address;}
| public void setAddress(Address address){this.address = address;}
|
| }
|
|
and in my client class LEFT JOIN FETCH syntax to fetch customer with lazy address object
public List<Customer> getCustomersLazyUsing(long cId) {
| String query = "select c from Customer c " +
| "left join fetch c.address" +
| " where c.id = :cId ";
and all work perfect
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