Java 一对一关系的JPA查询
我有一个EJB应用程序,在其中我将实体bean用于数据库。我必须创建具有单向一对一关系、JobPositionEntity和候选资格的实体bean 这是候选人资格 @实体 公共类候选资格扩展BaseEntity{Java 一对一关系的JPA查询,java,jpa,Java,Jpa,我有一个EJB应用程序,在其中我将实体bean用于数据库。我必须创建具有单向一对一关系、JobPositionEntity和候选资格的实体bean 这是候选人资格 @实体 公共类候选资格扩展BaseEntity{ private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; priv
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private Long meritNumber;
private String seatNumber;
private String candidateName;
private String gender;
public Long getMeritNumber() {
return meritNumber;
}
public void setMeritNumber(Long meritNumber) {
this.meritNumber = meritNumber;
}
public String getSeatNumber() {
return seatNumber;
}
public void setSeatNumber(String seatNumber) {
this.seatNumber = seatNumber;
}
public String getCandidateName() {
return candidateName;
}
public void setCandidateName(String candidateName) {
this.candidateName = candidateName;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
@Override
public Long getId() {
return id;
}
@Override
public void setId(Long id) {
this.id = id;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof CandidateEntity)) {
return false;
}
CandidateEntity other = (CandidateEntity) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "com.nisheeth.config.ejb.entity.CandidateEntity[ id=" + id + " ]";
}
}
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
@OneToOne(fetch = FetchType.EAGER, orphanRemoval = true, cascade = CascadeType.ALL)
private CandidateEntity candidate;
@ManyToOne(fetch = FetchType.EAGER)
private SeasonEntity season;
public SeasonEntity getSeason() {
return season;
}
public void setSeason(SeasonEntity season) {
this.season = season;
}
public CandidateEntity getCandidate() {
return candidate;
}
public void setCandidate(CandidateEntity candidate) {
this.candidate = candidate;
}
@Override
public Long getId() {
return id;
}
@Override
public void setId(Long id) {
this.id = id;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof JobPositionEntity)) {
return false;
}
JobPositionEntity other = (JobPositionEntity) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "com.nisheeth.config.ejb.entity.JobPositionEntity[ id=" + id + " ]";
}
}
这是JobPositionEntity
@实体
公共类JobPositionEntity扩展了BaseEntity{
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private Long meritNumber;
private String seatNumber;
private String candidateName;
private String gender;
public Long getMeritNumber() {
return meritNumber;
}
public void setMeritNumber(Long meritNumber) {
this.meritNumber = meritNumber;
}
public String getSeatNumber() {
return seatNumber;
}
public void setSeatNumber(String seatNumber) {
this.seatNumber = seatNumber;
}
public String getCandidateName() {
return candidateName;
}
public void setCandidateName(String candidateName) {
this.candidateName = candidateName;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
@Override
public Long getId() {
return id;
}
@Override
public void setId(Long id) {
this.id = id;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof CandidateEntity)) {
return false;
}
CandidateEntity other = (CandidateEntity) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "com.nisheeth.config.ejb.entity.CandidateEntity[ id=" + id + " ]";
}
}
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
@OneToOne(fetch = FetchType.EAGER, orphanRemoval = true, cascade = CascadeType.ALL)
private CandidateEntity candidate;
@ManyToOne(fetch = FetchType.EAGER)
private SeasonEntity season;
public SeasonEntity getSeason() {
return season;
}
public void setSeason(SeasonEntity season) {
this.season = season;
}
public CandidateEntity getCandidate() {
return candidate;
}
public void setCandidate(CandidateEntity candidate) {
this.candidate = candidate;
}
@Override
public Long getId() {
return id;
}
@Override
public void setId(Long id) {
this.id = id;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof JobPositionEntity)) {
return false;
}
JobPositionEntity other = (JobPositionEntity) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "com.nisheeth.config.ejb.entity.JobPositionEntity[ id=" + id + " ]";
}
}
我想选择不在JobPositionEntity中的候选人。我的查询不适用于我:
select ce.candidateName, ce.id from JobPositionEntity jp left join jp.candidate ce where ce <> null
从JobPositionEntity jp left join jp.candidateName,ce.id选择ce.candidateName,其中ce为null
有人能帮忙写这个查询吗?提前谢谢。您可以使用子查询
select c from Candidate c where c.id not in
(select jp.candidate.id from JobPositionEntity jp)
有关更多信息:
我看不到发布的JPQL和您想要的描述之间的任何关系。您能澄清一下吗?举个例子。如果您在JobPositionEntity中看到的是一对一的关系。这并不能澄清任何事情。假设您有J1-C1、J2-C2、J3 null、null-C4,其中J是一个JobPosition,而C是一个候选者。查询结果是什么你想找什么?