HIbernate #OneToOne mapping - java

I have a PatientVisit.java that has a one to one mapping with the PatientVisitObject.java:
#Entity
#Table(name = "P_Visit")
public class PatientVisit extends Bean {
#Id
#Column(name = "PATIENT_VISIT_SEQ")
private Long patientVisitSeq;
#Column(name = "PATIENT_FIRST_NM")
private String firstName;
#Column(name = "PATIENT_LAST_NM")
private String lastName;
#Column(name = "PATIENT_MIDDLE_NM")
private String middleName;
#OneToOne
private PatientVisitObject pvo;
}
The PatientVisitObject.java has a composite key. I need to map key.patientVisitSeq to my patientVisitSeq in the PatientVisit.java.
#Entity
#Table(name = "Patient_V_O")
public class PatientVisitObject extends Bean {
#Id
private PatientVisitObjectKey key;
#Column(name = "FIELD")
private String field;
}
Here is the key:
#Embeddable
public class PatientVisitObjectKey implements Serializable {
#Column(name = "PATIENT_VISIT_SEQ")
private Long patientVisitSeq;
#Column(name = "PATIENT_VISIT_OBJECT_SEQ")
private Long patientVisitObjectSeq;
}
I have tried using the #JoinTable annotation and cannot get it right. Could someone please give me some direction. Thanks.

You need to use bidirectional mapping with PatientVisit being the inverse side of relationship:
public class PatientVisit extends Bean {
...
#OneToOne(mappedBy = "pv")
private PatientVisitObject pvo;
...
}
public class PatientVisitObject extends Bean {
#EmbeddedId
private PatientVisitObjectKey key;
#OneToOne
#MapsId("patientVisitSeq")
private PatientVisit pv;
...
}
See also:
#MapsId

Related

Making primary key same as foreign key in Hibernate entity

I am new to Hibernate. I am working on two entities as follows:
Entity 1 is as follows:
#Entity
#Table(name = "vm_user")
public class VmUser implements Serializable {
private static final long serialVersionUID = 1L;
#Column(name = "created_by")
private String createdBy;
#Column(name = "last_modified_by")
private String lastModifiedBy;
#Column(name = "created_date")
private Instant createdDate;
#Column(name = "last_modified_date")
private Instant lastModifiedDate;
#OneToOne
#JoinColumn(unique = true)
private User user; <--- HOW WILL I DENOTE THIS PRIMARY KEY OF VMUSER ENTITY ?
In the associated table in mysql i.e. vm_user, user_id is both primary key as well as foreign key which refers to id of user table associated with User entity.
Entity 2 is as follows:
#Entity
#Table(name = "my_entity")
public class MyEntity implements Serializable {
private static final long serialVersionUID = 1L;
#Column(name = "created_by")
private String createdBy;
#Column(name = "last_modified_by")
private String lastModifiedBy;
#Column(name = "created_date")
private Instant createdDate;
#Column(name = "last_modified_date")
private Instant lastModifiedDate;
#ManyToOne
private A a;
#OneToOne
#JoinColumn(unique = true)
private B b;
In the associated table in mysql i.e. my_entity, primary key is a combination of id of a and id of b. I am not getting how to denote this in Hibernate entity MyEntity.
Regarding the same, I have gone through a few posts: Hibernate foreign key as part of primary key and JPA & Hibernate - Composite primary key with foreign key, but no getting idea how to do these two ?
The solution is #MapsId
For example
#Entity
#Table(name = "vm_user")
public class VmUser implements Serializable {
#Id
#Column(name = "user_id")
private Integer id;
#MapsId
#OneToOne
private User user;
You can also remove the #JoinColumn(unique = true) because #Id makes it unique already.
public class MyEntityPk implements Serializable {
private Integer aId;
private Integer bId;
// IMPORTANT: Override equals() and hashCode()
}
#IdClass(MyEntityPk.class)
#Entity
#Table(name = "my_entity")
public class MyEntity implements Serializable {
#Id
private Integer aId;
#Id
private Integer bId;
#MapsId("aId")
#ManyToOne
private A a;
#MapsId("bId")
#OneToOne
private B b;
Please find more information in the Hibernate documentation https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html#identifiers-derived
You need to use #EmbeddedId and #MapsId ,
#Entity
#Table(name = "vm_user")
public class VmUser implements Serializable {
#Id
#Column(name = "user_id")
private Integer id;
#MapsId("user_id")
#OneToOne
private User user;
}
You can do the same thing for MyEntity as below,
#Embeddable
class BKey {
private int aId;
private int bId;
}
#Entity
#Table(name = "my_entity")
public class MyEntity implements Serializable {
#EmbeddedId
private BKey primaryKey;
#MapsId("aId")
#ManyToOne
private A a;
#MapsId("bId")
#OneToOne
#JoinColumn(unique = true)
private B b;
}
VM Users class
public class VmUser implements Serializable {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private long id;
#OneToOne
#JoinColumn(name="ID")
private Users user;
Users class
public class Users implements Serializable {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private long id;
#OneToOne(mappedBy="user")
private VmUser vmUser;
A class
#Entity
public class A implements Serializable {
#Id
private long id;
#OneToMany(mappedBy="a")
private List<MyEntity> myEntitys;
B Class
#Entity
public class B implements Serializable {
#Id
private long id;
#OneToMany(mappedBy="b")
private List<MyEntity> myEntitys;
MyEntity class
#Entity
public class MyEntity implements Serializable {
private static final long serialVersionUID = 1L;
#EmbeddedId
private MyEntityPK id;
#ManyToOne
#JoinColumn(name="ID1")
private A a;
#ManyToOne
#JoinColumn(name="ID2")
private B b;
MyEntityPK class
#Embeddable
public class MyEntityPK implements Serializable {
#Column(insertable=false, updatable=false)
private long id1;
#Column(insertable=false, updatable=false)
private long id2;

How to make a foreign key in EmbeddedId to other Entity with other EmbeddedId

I have the class SWEntity that is central to the problem. I want set of classes SWEntityRow that is a detail of the SWEntity (one entity has many rows). The SWentity has in the key two other classes in the embeddedId Area and Procedure. When I try to map SWEntity with SWEntityRow using SWEntityRowId I take differents errors.
Some idea how I can map SWEntityRowId with SWEntity?
This is a simplified picture of the ER: https://i.stack.imgur.com/pMJzh.png
And this are my simplified classes:
SWentity
-----------
#Entity
public class SWEntity {
#EmbeddedId
private SWEntityId id;
[...]
}
SWEntityId
-------------
#Embeddable
public class SWEntityId implements Serializable{
private static final long serialVersionUID = 1L;
#NotNull
private String name;
#NotNull
private int version;
#ManyToOne
#JoinColumn(name = "areaName", nullable = false)
#JsonIgnore
private Area area;
#ManyToOne
#JoinColumn(name = "procedureName", nullable = false)
#JsonIgnore
private Procedure procedure;
}
SWEntityRow
---------------
#Entity
public class SWEntityRow{
#EmbeddedId
private SWEntityRowId sWEntityRowId;
}
SWEntityRowId
---------------
#Embeddable
public class SWEntityRowId implements Serializable {
private static final long serialVersionUID = 1L;
private String rowName;
//SWEntityId
#ManyToOne
#JoinColumns({
#JoinColumn(name="name_row", referencedColumnName="name"),
#JoinColumn(name="version_row", referencedColumnName="version"),
#JoinColumn(name="area_row", referencedColumnName="area_name"),
#JoinColumn(name="procedure_row", referencedColumnName="procedure_name"
})
}
This resolve my question
# JoinColumns({
#JoinColumn(name="entityname", referencedColumnName="name"),
#JoinColumn(name="entityversion", referencedColumnName="version"),
#JoinColumn(name="entityarea", referencedColumnName="AreaName"),
#JoinColumn(name="entityprocedure", referencedColumnName="ProcedureName")
})
The difference is in referencedColumnName="AreaName" not referencedColumnName="area_name" and the same for procedure.
Thanks!
Just one change required
#Entity
public class SWEntity {
#Id
#EmbeddedId
private SWEntityId id;
[...]
}

How to use #OnetoMany with Embeddedid

I am working on hibernate and tying to associate mapping with #OneToMany relationship with composite key.
Following are the entities that currently my using .
#Embeddable
#Getter
#Setter
public class AddressKey implements Serializable {
private static final long serialVersionUID = -307823488229761699L;
#Column(name = "id")
private Long id;
#Column(name = "city")
private Long city;
#Column(name = "locale")
private String locale;
#Column(name = "type")
private String type;
#ManyToOne
#JoinColumn(name="id")
private Person person;
}
#Entity
#Table(name = "address", schema = "test")
#Setter
#Getter
public class AddressHistory {
#EmbeddedId
private AddressKey key;
#Column(name = "active")
private boolean active;
#Column(name = "current")
private boolean current;
}
#Entity
#Table(name = "person", schema="test")
#ToString
public class Person {
#Id
#Column(name = "id")
private Long id;
#OneToMany(mappedBy="key.person", fetch=FetchType.EAGER, cascade=CascadeType.ALL)
private Set<AddressHistory> addressHistory;
}
But when I am trying to run this program it gives me following error.
repeated column in mapping for entity AddressHistory.
Someone help me to fix this what's wrong in this mapping.
Thanks in advance
You repeated columns. Remove #JoinColumn(name="id") in AddressKey since you already have one column with the same name or rename it to something else and more maintainable like person_id.

JPA mapping sports game with two #OneToOne relations

I have the following hierarchy for a football match.
#Entity
public class Match {
#Id
#GeneratedValue
protected Integer id;
#Column(name = "home_team_id")
private int homeTeamId;
#Column(name = "away_team_id")
private int awayTeamId;
private TeamScore homeScore;
private TeamScore awayScore;
}
#Entity(name = "team_score")
public class TeamScore {
#EmbeddedId
protected TeamScoreId id;
private List<Goal> goals;
}
#Embeddable
public class TeamScoreId {
#Column(name = "match_id")
private Integer matchId;
#Column(name = "team_id")
private int teamId;
}
And I have a problem with mapping homeScore and awayScore in Match with TeamScore entity.
The first concern is whether two #OneToOne relations should be here. And how should they be configured?
The second one relates to matchId in TeamScoreId. How this mapping can be performed?

Remove redundant column for composite key in Hibernate

Hibernate creates empty "ID" column in case of code like in this post.
How tune it to not create "ID" column ("ID" is exact name of created column) or this can not be changed?
#Entity
#Table(name = "CATEGORY_RELATIONS")
public class CategoryRelations implements Serializable {
private CategoryRelationsPrimaryKey id;
#Id
#Column(name = "CATEGORY_RELATIONS_CATEGORY_ID")
private String categoryId;
#Id
#Column(name = "CATEGORY_RELATIONS_PARENT_ID")
private String parentId;
//getters and setters
#Entity
#IdClass(CategoryRelationsPrimaryKey.class)
public class CategoryRelationsPrimaryKey implements Serializable {
protected long categoryId;
protected long parentId;
//euqals, hashCode
}
}
1) #IdClass should stand at entity, not at composite id class;
2) If you already marked id properties by #Id, no separate id property is required:
#Entity
#Table(name = "CATEGORY_RELATIONS")
#IdClass(CategoryRelationsPrimaryKey.class)
public class CategoryRelations implements Serializable {
#Id
#Column(name = "CATEGORY_RELATIONS_CATEGORY_ID")
private String categoryId;
#Id
#Column(name = "CATEGORY_RELATIONS_PARENT_ID")
private String parentId;
//...
}
public class CategoryRelationsPrimaryKey implements Serializable {
protected String categoryId;
protected String parentId;
// ...
}
If you need some property named id, make it transient to avoid mapping to a DB table column.

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