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.
Related
Suppose that I have a simple Hibernate entity with auto-incremented id.
#Entity
#Table(name = "product")
public class Product {
#Id
#GeneratedValue(strategy = IDENTITY)
private Long id;
private String name;
}
Is it possible to declare id as a type-safe variable? I could apply #EmbeddedId like this.
#Entity
#Table(name = "product")
public class Product {
#EmbeddedId
private ProductId id;
private String name;
#Embeddable
public static class ProductId implements Serializable {
#GeneratedValue(strategy = IDENTITY)
private Long id;
public Long getId() {
return id;
}
}
}
It works with client-generated IDs, but not with database-generated ones.
Has anyone solved similar problem? What are the possible approaches?
First, you need to annotate ProductId class with #Embeddable like this:
#Embeddable
public static class ProductId implements Serializable {
private Long id;
private String name;
}
And, when you save entity, you need to create an instance of ProductId with unique parameters (in your case it is "name" field) as well.
For more information, I suggest you to have a look at here
I have object with #Id (primary key) and this is some business UIID field and I want another Long technical Id for some reasons but when saving the object I get null from getObjectId field:
#Id
private String id;
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "object_id")
private Long objectId;
public Long getObjectId() {
return objectId;
}
public void setObjectId(Long objectId) {
this.objectId = objectId;
}
I have this storage class:
interface MyObjectStorage extends JpaRepository<MyObject, String>
And this is how I save it:
final MyObject saved = storage.saveAndFlush(toSave);
saved.objectId is null here..
And in my MySQL db the objectId field is marked not null auto increment..
PS. And I don't want this objectId field to be used by JPA when findById is executed.
Hibernate/JPA isn't able to automatically create a value for your non-id-properties. The #GeneratedValue annotation is only used in conjunction with #Id to create auto-numbers.
The solution (or work-around) suggested in this forum is to create a separate entity with a generated Id, something like this:
#Entity
public class GeneralSequenceNumber {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "object_id")
private Long objectId;
}
#Entity
public class MyEntity {
#Id ..
private Long id;
#OneToOne(...)
private GeneralSequnceNumber myVal;
}
try the following code
#Id must be a type of Integer or Long
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "object_id")
private Long objectId;
private String id;
public Long getObjectId() {
return objectId;
}
public void setObjectId(Long objectId) {
this.objectId = objectId;
}
interface MyObjectStorage extends JpaRepository<MyObject, Long>
I have a Question Entity and Tag entity with getter, setter methods and a OneToMany relationship from question to tag and a OneToOne relationship from question to user
public class Question {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
#Column(name="title")
private String title;
#Column(name="body")
private String body;
#Temporal(TemporalType.DATE)
#Column(name="date_created")
private Date date_created;
#OneToOne(cascade=CascadeType.ALL)
#JoinColumn(name="user_id")
private User user;
#OneToMany(cascade=CascadeType.ALL)
#JoinColumn(name="tag_id")
private Tag tag;
#Column(name="answer_count")
private int answer_count;
#Column(name="view_count")
private int view_count;
public Question() {
}
Tag entity
public class Tag {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
#Column(name="name")
private String name;
#Column(name="username")
private String username;
#Temporal(TemporalType.DATE)
#Column(name="date_created")
private Date date_created;
public Tag() {
}
When I try to insert a question using Postman with the following details:
{
"title": "stefanyyyxx",
"body": "stefandoyee44",
"date_created": "2019-02-27",
"user_id" : 1,
"tag_id": 1,
"answer_count": 0,
"view_count": 0
}
QuestionRepository.java:
#Override
public void save(Question theQuestion) {
// get the current hibernate session
Session currentSession = entityManager.unwrap(Session.class);
// save employee
currentSession.saveOrUpdate(theQuestion);
}
Null values are being inserted for user_id and tag_id though I used JoinColumn().
MySQL:
As #Karol Dowbecki Suggested,
convert the JSON to DTO object and use that DTO to get the User, Tag Entities from their respective repositories.
Finally create the Question entity object and store it.
Question Entity
#Entity
#Table(name = "question")
public class Question {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "title")
private String title;
#Column(name = "body")
private String body;
#Temporal(TemporalType.DATE)
#Column(name = "date_created")
private Date dateCreated;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "user_id")
private User user;
#OneToMany(cascade = CascadeType.ALL)
#JoinColumn(name = "tag_id")
private Set<Tag> tag;
#Column(name = "answer_count")
private int answerCount;
#Column(name = "view_count")
private int viewCount;
}
User Entity
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
}
Tag Entity
#Entity
#Table(name = "tag")
public class Tag {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "name")
private String name;
#Column(name = "username")
private String username;
#Temporal(TemporalType.DATE)
#Column(name = "date_created")
private Date dateCreated;
}
DTO Class
public class QuestionDTO {
private Long id;
private String title;
private String body;
private Date dateCreated;
private Long user;
private Long tag;
private int answerCount;
private int viewCount;
}
Test Class
#Service
public class TestService {
#Autowired
private QuestionRepository questionRepository;
#Autowired
private UserRepository userRepository;
#Autowired
private TagRepository tagRepository;
public void addQuestion(QuestionDTO dto) {
Tag tag = null;
User user = null;
Question question = null;
Set<Tag> tags = null;
tag = tagRepository.findById(dto.getTag());
tags = new HashSet<>();
tags.add(tag);
user = userRepository.findById(dto.getUser());
question = new Question();
question.setTag(tags);
question.setUser(user);
question.setId(dto.getId());
question.setBody(dto.getBody());
question.setTitle(dto.getTitle());
question.setViewCount(dto.getViewCount());
question.setAnswerCount(dto.getAnswerCount());
question.setDateCreated(dto.getDateCreated());
questionRepository.save(question);
}
}
NOTE :
The relation between Question and Tag are in OneToMany you have to use Collection type.
You have a mismatch between JSON and #Entity structure. JSON contains numeric identifiers while the #Entity contains actual objects representing relationships. You most likely should introduce a separate DTO class to map this JSON while in #Repository you should load User and Tag objects based on their id or create new ones. You already have CascadeType.ALL so Hibernate will cascade the persist operation.
Generally the controller layer should be separate from repository layer unless you are doing something very, very simple. This helps to evolve the service without changing the API contract e.g. adding new columns for auditing changes. By exposing the #Entity as DTO you make your life harder down the road.
You should add referencedColumnName in your Child Entity Foreign Key Column
referencedColumnName="your primaray key column name"
EDIT:
referencedColumnName
The name of the column referenced by this foreign key column.
When used with entity relationship mappings other than the cases
described here, the referenced column is in the table of the target
entity.
When used with a unidirectional OneToMany foreign key mapping, the
referenced column is in the table of the source entity.
When used inside a JoinTable annotation, the referenced key column is
in the entity table of the owning entity, or inverse entity if the
join is part of the inverse join definition.
When used in a CollectionTable mapping, the referenced column is in
the table of the entity containing the collection.
Default (only applies if single join column is being used): The same
name as the primary key column of the referenced table.
Asset is Parent Entity and AssetDetails is Child Entity
Here I have taken OneToOne Relationship
Asset.java
#Entity
#Table(name="asset")
public class Asset {
#Id
#GeneratedValue
#Column(name="assetid")
private BigInteger assetid;
#OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "asset")
#JsonBackReference
private AssetDetails assetDetails;
public AssetDetails getAssetDetails() {
return assetDetails;
}
public void setAssetDetails(AssetDetails assetDetails) {
this.assetDetails = assetDetails;
assetDetails.setAsset(this);
}
public Asset(your fields, AssetDetails assetDetails) {
super();
// your fields
this.assetDetails = assetDetails;
this.assetDetails.setAsset(this);
}
public Asset() {
super();
}
public BigInteger getAssetid() {
return assetid;
}
public void setAssetid(BigInteger assetid) {
this.assetid = assetid;
}
}
AssetDetails.java
#Entity
#Table(name="assetDetails")
public class AssetDetails {
#Id
#GeneratedValue
private BigInteger assetdetailid;
#JoinColumn(name = "assetid",nullable = false, updatable = false,referencedColumnName="assetid")
#OneToOne(cascade=CascadeType.ALL)
#JsonManagedReference
private Asset asset;
public Asset getAsset() {
return asset;
}
public void setAsset(Asset asset) {
this.asset = asset;
}
public AssetDetails(your fields,Asset asset) {
super();
//your fields
this.asset = asset;
}
}
I have the next relationship:
Currently, I have the next code:
#Embedded
public class StockPK implements Serializable {
private int storeId;
private int productId
}
#Entity
public class Stock implements Serializable {
#EmbeddedId
private StockPK id;
private int cantidad;
#ManyToOne
private Store store;
#ManyToOne
private Product product;
}
But the DDL generated (I'm using OpenJPA in TomEE) adds two aditional fields.
CREATE TABLE STOCK (
productId INTEGER NOT NULL,
storeId INTEGER NOT NULL,
quantity INTEGER NOT NULL,
PRODUCT_ID INTEGER ,
STORE_ID INTEGER ,
PRIMARY KEY (productId, storeId)
)
How should specify this relationship?
Thanks JBNizet :) — The solution was as follows:
#Embeddable
public class StockPK implements Serializable {
#Column(name = "store_id")
private int storeId;
#Column(name = "product_id")
private String productId;
// Getters, setters, hashCode, equals
}
#Entity
#Table(name = "stock")
public class Stock implements Serializable {
#EmbeddedId
private StockPK id;
#MapsId("storeId")
#ManyToOne
private Store store;
#MapsId("productId")
#ManyToOne
private Product product;
#Column(nullable = false)
private int quantity;
// Getters, setters
}
#Entity
#Table(name = "store")
public class Store implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
// Other fields, getters, setters ...
}
#Entity
#Table(name = "product")
public class Product implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
// Other fields, getters, setters ...
}
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