I have an existing database schema and I try to make one to many relationship in JPA when PK is a composite of multiple fields and just one of them is FK in the other entity:
DemandId: PK class that consist of two fields
#Embeddable
public class DemandId implements Serializable {
#Column(name = "\"ORDER\"", nullable = false)
private String order;
#Column(name = "SNRP", nullable = false)
private String number;
}
DemandEntity: The entity itself
#Entity
#Table(name = "DEMAND")
public class DemandEntity implements Serializable {
#EmbeddedId
private DemandId id;
#OneToMany(fetch = EAGER, cascade = ALL, mappedBy = "demand")
private Set<PartEntity> parts = new HashSet<>();
}
PartEntity:
#Entity
#Table(name = "PART")
public class PartEntity implements Serializable {
#Column(name = "SNRP")
private String number;
#ManyToOne
#JoinColumn(name = "SNRP", referencedColumnName = "SNRP", insertable = false, updatable = false)
private DemandEntity demand;
}
This approach leads to an exception:
Exception Description: The #JoinColumns on the annotated element
[field demand] from the entity class [class PartEntity] is incomplete.
When the source entity class uses a composite primary key, a
#JoinColumn must be specified for each join column using the
#JoinColumns. Both the name and the referencedColumnName elements must
be specified in each such #JoinColumn.
Unfortunatelly I cannot add another join column
#JoinColumn(name = "\"ORDER\"", referencedColumnName = "\"ORDER\"", insertable = false, updatable = false)
Because the PART table doesn't contain the ORDER field and the structure of the database cannot be changed.
Is there a way to perform such mapping?
Regards
If you have composite primary keys and you want to have one to many
mapping, I would suggest rather than keeping those keys as composite
primary keys, make them composite unique keys.
And make a auto-generated sequence as a primary key.
It is better and more convenient. By the way its my personnel opinion.
I even don't know, if that is possible or not which you are trying to do.
Related
Scenario:
I have a products table with these fields: id, code, description, photo.
I have a product_stock view from other schema with fields: prod_code, stok_tot
Misson: What I need to do in Spring Boot is to join the products with their total stock.
Rules:
I can't use #Query on this task, I need to join them at the Product Entity Class, so that stock became some kind of Transient field of product.
I can't change the fact that product's ID is a Long and ProductStock's ID is a String, but I could use product's code field instead right? (how?)
So far... I tryed to use #OneToOne and #JoinColumn to do the job, but my REST gives me the stock field as NULL.
"Estoque.java"
#Entity
#Table(name = "VW_ESTOQUE", schema = "ASICAT")
public class Estoque {
#Id
#Column(name = "CD_BEM_SERVICO", unique = true, nullable = false)
private String codigo;
#Column(name = "ESTOQUE")
private Long estoque;
// getters and setters hidden by me
}
"Produto.java"
#Entity
#NamedEntityGraph(name = "Produto.detail", attributeNodes = #NamedAttributeNode("categorias"))
public class Produto implements Serializable {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE)
private Long id;
private String codigo;
private String descricao;
// here is where I get the null values
#Transient
#OneToOne(fetch = FetchType.LAZY)
#JoinTable(name = "VW_ESTOQUE", joinColumns = #JoinColumn(name = "CODIGO", referencedColumnName = "CODIGO"), inverseJoinColumns = #JoinColumn(name = "CD_BEM_SERVICO", referencedColumnName = "CODIGO"))
private Estoque estoque;
private String hash;
#ManyToMany(mappedBy = "produtos", fetch = FetchType.EAGER)
#BatchSize(size = 10)
private List<Categoria> categorias = new ArrayList<>();
// getters and setters hidden by me
}
In my product repository I call FindAll()
You have annotated Produto.estoque as #Transient, which means that it is not part of the persistent state of the entity. Such a field will be neither written nor read when instances of that entity are managed. That's not going to serve your purpose.
There are two things I can imagine you might have been trying to achieve:
That every time an Estoque is accessed via a Produto, it should be loaded from the DB to ensure its freshness. JPA does not provide for that, though you might want to annotate Estoque with #Cacheable(value = false), and specify the lazy fetch strategy on the Produto side of the relationship.
You want to avoid the persistence provider attempting to persist any changes to an Estoque, since it is backed by a view, not an updatable table. This we can address.
My first suggestion would be to map ASICAT.VW_ESTOQUE as a secondary table instead of an entirely separate entity. That might look something like this:
#Entity
#SecondaryTable(name = "VW_ESTOQUE", schema = "ASICAT"
pkJoinColumns = {
#PrimaryKeyJoinColumn(name = "CD_BEM_SERVICO",
referencedColumnName = "CODIGO") })
public class Produto implements Serializable {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE)
private Long id;
private String codigo;
private String descricao;
#Column(name = "ESTOQUE", table = "VW_ESTOQUE", nullable = true,
insertable = false, updatable = false)
private Long estoque;
// ...
}
You might furthermore avoid providing a setter for the estoque property.
But the SecondaryTable approach might not work well if you cannot rely on the ESTOQUE view always to provide a row for every row of PRODUTO, as there will very likely be an inner join involved in retrievals. Moreover, you don't get lazy fetches this way. The main alternative is more or less what you present in your question: to set up a separate Estoque entity.
If you do set up a separate Estoque, however, then I would approach it a bit differently. Specifically,
I would make the relationship bidirectional, so that I could
make the Estoque entity the relationship owner.
Something like this, then:
#Entity
public class Produto implements Serializable {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE)
private Long id;
private String codigo;
private String descricao;
// must not be #Transient:
#OneToOne(fetch = FetchType.LAZY, mappedBy = "produto", cascade = {
CascadeType.REFRESH
})
private Estoque estoque;
// ...
}
#Entity
#Table(name = "VW_ESTOQUE", schema = "ASICAT")
#Cacheable(value = false)
public class Estoque {
#Id
#Column(name = "CD_BEM_SERVICO", nullable = false,
insertable = false, updatable = false)
private String codigo;
#Column(name = "ESTOQUE", insertable = false, updatable = false)
private Long estoque;
#OneToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "CD_BEM_SERVICO", referencedColumnName = "CODIGO",
nullable = false, insertable = false, updatable = false, unique = true)
Produto produto;
// getters and setters hidden by me
}
In this case, I would avoid providing setter methods for any of the properties of Estoque, and avoid providing any constructor that allows initial property values to be set. Thus, to a first approximation, the only
way an instance's properties will take non-null values is if they are set by the persistence provider.
Additionally, since you mention Oracle, if you are using TopLink as your persistence provider then you might consider applying its #ReadOnly extension attribute to the Estoque entity, in place of or even in addition to some of these protections against trying to insert into or update the view.
I'm using spring-boot 1.5.4 with spring-data-jpa and I'm trying to override the auto generated foreign key name during spring.jpa.hibernate.ddl-auto=create.
For simple id, I was able to override it: simple_fk
Hibernate: alter table my_entity add constraint simple_fk foreign key (simple_id) references simple
But not for foreign key with composite id: FKms12cl9ma3dk8egqok1dasnfq
Hibernate: alter table my_entity add constraint FKms12cl9ma3dk8egqok1dasnfq foreign key (composite_id1, composite_id2) references composite
What is wrong with my code? I also tried #PrimaryKeyJoinColumn.
Please see the class definitions below.
#Entity
public class Simple {
#Id
private long id;
}
#Entity
public class Composite {
#Id
private CompositeId id;
}
#Embeddable
public class CompositeId {
#Column
private long id1;
#Column
private long id2;
}
#Entity
public class MyEntity {
#ManyToOne
#JoinColumn(foreignKey = #ForeignKey(name = "simple_fk"),
name = "simple_id", referencedColumnName = "id")
private Simple simple;
#ManyToOne
#JoinColumns(foreignKey = #ForeignKey(name = "composite_fk"), value = {
#JoinColumn(name = "composite_id1", referencedColumnName = "id1"),
#JoinColumn(name = "composite_id2", referencedColumnName = "id2")
})
private Composite composite;
}
This is a known issue with the Hibernate which was fix in version 5.2.8
So there are two ways to fix it: Either you update the Hibernate to the version 5.2.8 or up by adding
<hibernate.version>5.2.10.Final</hibernate.version>
to your pom.xml, which basically will update the Hibernate to the latest version.
or if Hibernate update is not possible or is just too risky you can add legacy/deprecated #org.hibernate.annotations.ForeignKey(name = "composite_fk") annotation on your
composite field which will make you code look like
#Entity
public class MyEntity {
#ManyToOne
#JoinColumn(foreignKey = #ForeignKey(name = "simple_fk"), name = "simple_id", referencedColumnName = "id")
private Simple simple;
#ManyToOne
#JoinColumns(foreignKey = #ForeignKey(name = "composite_fk"), value = {
#JoinColumn(name = "composite_id1", referencedColumnName = "id1"),
#JoinColumn(name = "composite_id2", referencedColumnName = "id2") })
#org.hibernate.annotations.ForeignKey(name = "composite_fk")
private Composite composite;
}
I am trying to build a bidirectional one to many relationship with the spring data jpa but the list annotated with #onetomany always return one element.
Here is the code for my entities(setters and getters omitted):
#Entity
#Table(name = "sdk_sdk")
public class SDKEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
private String version;
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "sdk")
#OrderBy("order ASC")
private List<SDKFileEntity> fileEntities;
}
And the second entity:
#Entity
#Table(name = "sdk_file")
public class SDKFileEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
private String fileType;
private Integer sdkId;
public SDKFileEntity() {
}
#ManyToOne
#JoinColumn(name = "id", insertable = false, updatable = false)
private SDKEntity sdk;
I am trying to have a manytoone mapping where the sdkId corresponds to the id from the SDKEntity class.
Whenever I try to get the sdkfiles from the sdkEntity using spring's repository, the size of the list is always 1.
So for example:
SDKEntity entity=repository.findOne(foo);
List<SDKFileEntity> files=entity.getFileEntities();
here the size of files is 1, I have to delete the first element from the database to obtain the second element.
For me the reason here was that a parent entity implemented equals and hashcode
and unfortunately in a way that all existing entities were equal.
And non of the child entities implemented it herself.
So then the #OneToMany relation returned only the first element.
Took me quite some time.
This part of Code looks suspicious
#ManyToOne
#JoinColumn(name = "id", insertable = false, updatable = false)
private SDKEntity sdk;
name = "id" it should be actual column name as written in database column name like this
#JoinColumn(name = "VISIT_ID", referencedColumnName = "ID")
#ManyToOne
private Visit visitId;
I have the following situation:
I´m trying to build an application which is multi-tenant with the same tenants in one database
with the same tables. As by know Hibernate is not supporting this variant before 5.0 as I found.
I`m trying to solve this by adding a brandId field to every table.
As I build Many To Many relationships I also added this brandId to the ManyToMany Join Table and here (dont know if I can do this, mysql is not complaining) I made a foreign key to both tables while both include the brandid
So now for example I have a table Text(ID,name,brandId) and a Tag(ID,name,brandId) and a join table (text_id,tag_id,brand_id) where the foreign keys are
CONSTRAINT FK_TAG_TEXTS_TAG FOREIGN KEY (TAG_ID,BRAND_ID) REFERENCES TAG (ID,brand),
CONSTRAINT FK_TAG_TEXTS_TEXT FOREIGN KEY (TEXT_ID,BRAND_ID) REFERENCES TEXT (ID,brand)
As you can see Brand ID is used twice.
Then I generated my classes with Hibernate Tools, which created a Composite Primary Key Class as it should and the association in the Tag Class.
#ManyToMany(fetch = FetchType.EAGER,cascade = {CascadeType.PERSIST,CascadeType.MERGE })
#JoinTable(name = "tag_texts", , joinColumns = {
#JoinColumn(name = "TAG_ID", nullable = false, insertable = false, updatable = false),
#JoinColumn(name = "BRAND_ID", nullable = false, insertable = false, updatable = false) }, inverseJoinColumns = { #JoinColumn(name = "TEXT_ID", insertable = false, nullable = false, updatable = false),#JoinColumn( name = "BRAND_ID", insertable = false, nullable = false, updatable = false) })
public List<Text> getTexts() {
return this.texts;
}
The problem is now that I get the following exception:
org.hibernate.MappingException: Repeated column in mapping for collection: de.company.domain.Tag.texts column: brand_id
I looked into the Hibernate code in the Collection class which raises the exception.
Here a method 'checkColumnDupliation' is called which uses a Set and inserts the name,
what means that a second time inserting "BRAND_ID" as column leads to this behaviour.
As I found the most common solution for the Repeated column error is by inserting 'insertable = false and updateable = false' when using the same column in several references. This is described here:
Hibernate: Where do insertable = false, updatable = false belong in composite primary key constellations involving foreign keys?
But this seems to be not the same problem as mine.
So my question is: Is there a possibility to fix this with the JPA Annotations and use the Brand ID in both joinColumns and inverseJoinColumns?
The problem is that you want a JoinTable between 3 entities: Text, Tag and Brand.
Probably you will have to use an IdClass, something like :
public class AssociationId implements Serializable {
private long textId;
private long tagId;
private long brandId;
hash and equals function
...
}
Id Class Entity:
#Entity
#Table(name="tag_text_brand")
#IdClass(AssociationId.class)
public class TagTextBrandAssociation {
#Id
private long tagId;
#Id
private long textId;
#Id
private long textId;
#ManyToOne
#PrimaryKeyJoinColumn(name="TAG_ID", referencedColumnName="ID")
private Tag tag;
#ManyToOne
#PrimaryKeyJoinColumn(name="TEXT_ID", referencedColumnName="ID")
private Text text;
#ManyToOne
#PrimaryKeyJoinColumn(name="BRAND_ID", referencedColumnName="ID")
private Brand brand;
...
}
You can use this in your 3 entities like this:
#Entity
public class Text {
#Id
private long id;
...
#OneToMany(mappedBy="text")
private List<TagTextBrandAssociation> tagsAndBrands;
...
}
See here for more information.
I'm using Hibernate and Oracle database and just got stuck.
I'm trying to map this table:
CREATE TABLE passengers_on_the_flight
(
flight_id NUMERIC(10) REFERENCES flight(flight_id),
passenger_id NUMERIC(20) REFERENCES passenger(passenger_id),
seat NUMERIC(5) NOT NULL,
CONSTRAINT "not free" PRIMARY KEY (flight_id,passenger_id,seat)
);
So my mapping class looks like:
#Entity
#Table(name = "PASSENGERS_ON_THE_FLIGHT")
#NamedQueries({
#NamedQuery(name = "PassengersOnTheFlight.findAll", query = "SELECT p FROM PassengersOnTheFlight p")})
public class PassengersOnTheFlight implements Serializable {
private static final long serialVersionUID = 1L;
#EmbeddedId
protected PassengersOnTheFlightPK passengersOnTheFlightPK;
public PassengersOnTheFlightPK getPassengersOnTheFlightPK() {
return passengersOnTheFlightPK;
}
public void setPassengersOnTheFlightPK(PassengersOnTheFlightPK passengersOnTheFlightPK) {
this.passengersOnTheFlightPK = passengersOnTheFlightPK;
}
#JoinColumn(name = "SEAT", referencedColumnName = "SEAT", insertable = false, updatable = false)
private int seat;
#JoinColumn(name = "FLIGHT_ID", referencedColumnName = "FLIGHT_ID", insertable = false, updatable = false)
#ManyToOne
private Flight flight;
#JoinColumn(name = "PASSENGER_ID",referencedColumnName = "PASSENGER_ID",insertable = false, updatable = false)
#ManyToOne
private Passenger passenger;
//Getters, setters for seat, flight and passanger
And primary key class:
#Embeddable
public class PassengersOnTheFlightPK implements Serializable {
#Column(name = "FLIGHT_ID",nullable=false)
private long flightId;
#Column(name = "SEAT",nullable=false)
private int seat;
#Column(name = "PASSENGER_ID", nullable=false)
private Long passengerId;
//Getters and setters for seat, flightId and passangerId
I tried to persist something and got
ORA-00957: duplicate column name
That because Hibernate generates such query:
insert into PASSENGERS_ON_THE_FLIGHT (seat, FLIGHT_ID, PASSENGER_ID, SEAT) values (?, ?, ?, ?)
I don't get why. Did I mis something in the mapping classes?
I get the same problem with a Coposite Key and solved it adding this params at the #JoinColumn hibernate annotation in the get methods of the external PK duplicate entities:
#JoinColumn(..., updatable=false, insertable=false)
Hibernate really REALLY wants you to have a unique identity key for each table; it has "issues" without it. Try putting an identity key on your table.
You get your error because you specified seat twice. Once you have it as property of your entity PassengersOnTheFlight and second time in the key. If it is part of your key, remove it from the main object. If it is an integer, you probably don't want #JoinColumn for it anyway.