我正在使用JPA进行映射,我有这个实体类

@Entity
@Table(name = "h_pe")
@XmlRootElement
@NamedQueries({

public class HPe implements Serializable {
 private static final long serialVersionUID = 1L;
 @EmbeddedId
 protected HPePK hPePK;
 @Column(name = "PE_TIMEOUT")
 private Integer peTimeout;
 @Column(name = "PE_STATUS")
 private Boolean peStatus;
 @OneToMany(cascade = CascadeType.ALL, mappedBy = "hPe")
 private Collection<HPesp> hPespCollection;
 @JoinColumn(name = "PE_ENV", referencedColumnName = "ENV_URL", insertable = false, updatable = false)
 @ManyToOne(optional = false)
 private HEnv hEnv;
 @JoinColumn(name = "PE_PLATFORM", referencedColumnName = "PLATFORM_NAME", insertable = false, updatable = false)
 @ManyToOne(optional = false)
 private HPlatform hPlatform;

}


我想编写一个如下的请求JPA(我已经用SQl编写了它),我试图编写它,但是我不知道如何使用PE_ENV,因为它是OneToMany关系的结果!

select distinct h_env.env_name,h_platform.PLATFORM_NAME
from h_env,h_platform,h_pe
where h_env.ENV_URL=h_pe.PE_ENV
and h_platform.PLATFORM_NAME=h_pe.PE_PLATFORM
and h_platform.PLATFORM_NAME='XXX';

最佳答案

Select e.name, p.name
from HPe hp join hp.hPlatform p join hp.hPespCollection p
where p.name = 'xxx'


看到,
http://en.wikibooks.org/wiki/Java_Persistence/Querying#Common_Queries

10-07 19:48
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