I want to create a double self-reference entity using an extra join table. I tried thus the following :
#Entity
#Table(name = "entity_a", schema="schema_a")
public class EntityA{
#Id
#Column(name = "id", unique = true, nullable = false)
private UUID id = UUID.randomUUID();
//skipped source code...
#OneToOne(fetch = FetchType.LAZY)
#JoinTable(name = "origin_child",
joinColumns =
{ #JoinColumn(name = "origin_id", referencedColumnName = "id", nullable = false)},
inverseJoinColumns =
{ #JoinColumn(name = "child_id", referencedColumnName = "id", nullable = false)})
private EntityA child;
#OneToOne(fetch = FetchType.LAZY)
#JoinTable(name = "origin_child",
joinColumns =
{ #JoinColumn(name = "child_id", referencedColumnName = "id", nullable = false)},
inverseJoinColumns =
{ #JoinColumn(name = "origin_id", referencedColumnName = "id", nullable = false)})
private EntityA origin;
//skipped source code...
}
When running my code I get the following error : org.hibernate.boot.spi.InFlightMetadataCollector$DuplicateSecondaryTableException: Table with that name [origin_child] already associated with entity
I tried thus to remove the origin field from EntityA and it worked. Now I am trying to figure out a way to join my EntityA.id and EntityA.origin_id over the already existing origin_child.child_id and origin_child.origin_id. Any idea how may I achieve that. Any alternative or better solution is more than welcome.
UPDATE :
I have tried the #JoinColumn alternative as following :
#OneToOne(fetch = FetchType.LAZY, mappedBy = "child")
private EntityA origin;
#OneToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "child_id", referencedColumnName = "id", nullable = true)
private EntityA child;
Now when trying to update both origin and child instances :
child.setOrigin(origin);
entityARepository.save(child);
origin.setChild(child);
entityARepository.save(origin);
I get java.lang.StackOverflowError due to infinite recursion.
Any work around please?
Related
I have manyToMany relationship mapping and couldn't get it to work. I have read many posts and articles and couldn't figure this one out. If anyone has some idea please share.
I have tried to simplify diagram and code as much.
My database is designed like this:
My entities look like this (at least final attempt before asking):
Client:
#Entity
#Table(name = "client")
public class Client implements Serializable {
#Id
#Column(name = "client_id")
private int id;
... other fields
}
Project:
#Entity
#Table(name = "project")
public class Project implements Serializable {
#EmbeddedId
private ProjectId id;
... other fields
#Embeddable
class ProjectId implements Serializable {
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "client_id", insertable = false, updatable = false)
private Client client;
#Column(name = "project_id")
private int projectId;
}
}
User:
#Entity
#Table(name = "user")
public class User implements Serializable {
#EmbeddedId
private UserId id;
... other fields
#Embeddable
class UserId implements Serializable {
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "client_id", insertable = false, updatable = false)
private Client client;
#Column(name = "user_id")
private int userId;
}
}
ProjectUser:
#Entity
#Table(name = "project_user")
public class ProjectUser implements Serializable {
#EmbeddedId
private ProjectUserId id;
... other fields
#Embeddable
class ProjectUserId implements Serializable {
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "client_id", insertable = false, updatable = false)
private Client client;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumns({
#JoinColumn(name = "client_id", referencedColumnName = "client_id", insertable = false, updatable = false),
#JoinColumn(name = "project_id", referencedColumnName = "project_id", insertable = false, updatable = false) })
private Project project;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumns({
#JoinColumn(name = "client_id", referencedColumnName = "client_id", insertable = false, updatable = false),
#JoinColumn(name = "user_id", referencedColumnName = "user_id", insertable = false, updatable = false) })
private User user;
}
}
Before adding ProjectUser entity everything is working fine.
Now when I'm starting server it says:
Repeated column in mapping for entity: ProjectUser column: client_id
(should be mapped with insert=\"false\" update=\"false\")"}}
So, the question is how do I make this work?
EDIT:
Java application will be mostly REST services providing data. Database design is as is. It has logical sense and most of the business logic will be in database. We have people with very good DB knowledge working on this and it would not make much sense changing database design because of JPA/Hibernate limitations.
The code below will let hibernate create a structure for your entities:
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "client_id", insertable = false, updatable = false)
private Client client;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumns({
#JoinColumn(name = "project_client_id", referencedColumnName = "client_id", insertable = false, updatable = false),
#JoinColumn(name = "project_id", referencedColumnName = "project_id", insertable = false, updatable = false) })
private Project project;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumns({
#JoinColumn(name = "user_client_id", referencedColumnName = "client_id", insertable = false, updatable = false),
#JoinColumn(name = "user_id", referencedColumnName = "user_id", insertable = false, updatable = false) })
private User user;
But to make a scheme as on the picture in your question, get rid of all these EmbeddedId. Use simple ids and add validation in your code, if you want project and user inside your ProjectUser have the same client_id.
I have a following example I want to create a lazy #ManyToOne relation between Car and CarAchievement tables using multiple join columns (example of class below)
#Entity
#Table(name = "CAR")
public class Car implements Serializable {
#Id
#GenericGenerator(name = "SEQ_CAR", strategy = "sequence",
parameters = {
#org.hibernate.annotations.Parameter(
name = "sequence",
value = "SEQ_CAR"
)
}
)
#GeneratedValue(generator = "SEQ_CAR")
#Column(name = "ID")
private Integer id;
#ManyToOne(fetch = FetchType.LAZY)
#NotFound(action = NotFoundAction.IGNORE)
#JoinColumns({
#JoinColumn(name = "region", referencedColumnName = "region", updatable = false, insertable = false),
#JoinColumn(name = "model", referencedColumnName = "model", updatable = false, insertable = false),
#JoinColumn(name = "year", referencedColumnName = "type", updatable = false, insertable = false),
#JoinColumn(name = "type", referencedColumnName = "year", updatable = false, insertable = false)
})
#JsonIgnore
private CarAchievement carAchievement;
}
This relation works fine but it seems not to be a LazyFetch, every query for a CAR seems to be fetching CarAchievement automatically even when its not specified to fetch this relation
Hibernate version: 4.3.10.Final
I have a LibraryModel class, a LibraryImage class and a LibraryAttribute class. A LibraryModel can have an arbitrary number of LibraryImages and LibraryAttributes.
The error that I get:
org.hibernate.MappingException: Foreign key (FKmbn4xh7xdxv371ao5verqueu3:library_item_attribute [LIBRARY_ITEM_ATTRIBUTE_ID])) must have same number of columns as the referenced primary key (library_item_attribute [LIBRARY_ITEM_ID,LIBRARY_ITEM_ATTRIBUTE_ID])
Here are my annotated Objects:
Library Model:
#Entity
#Table(name = "library_item", uniqueConstraints = {
})
#Inheritance(strategy = InheritanceType.JOINED)
public class LibraryItemModel implements LibraryItem{
#Id
#GeneratedValue(strategy = IDENTITY)
#Column(name = "LIBRARY_ITEM_ID", unique = true, nullable = false)
private Integer libraryItemId;
#Column(name = "ITEM_TITLE", unique = false, nullable = false)
private String itemTitle;
#Column(name = "IS_PARENT", nullable = false)
private Boolean isParent;
#ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JoinColumn(name="LIBRARY_ID", nullable = false)
private LibraryModel libraryModel;
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinTable(name = "ITEM_LISTING",
joinColumns = {#JoinColumn(name = "PARENT_LIB_ITEM_ID", nullable=false)},
inverseJoinColumns = {#JoinColumn(name="CHILD_LIB_ITEM_ID", nullable = false)})
private Set<LibraryItemModel> itemChildren = new HashSet<>();
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "itemChildren")
private Set<LibraryItemModel> itemParents = new HashSet<>();
#ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JoinTable(name = "LIBRARY_ITEM_IMAGE",
joinColumns = { #JoinColumn(name = "LIBRARY_ITEM_ID", nullable=false)},
inverseJoinColumns = { #JoinColumn(name="LIBRARY_IMAGE_ID", nullable = false)})
private Set<LibraryImage> itemImages = new HashSet<>();
#OneToMany(fetch = FetchType.LAZY, mappedBy = "rootLibraryItemModel")
private Set<LibraryModel> libraries = new HashSet<>();
#ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JoinTable(name = "LIBRARY_ITEM_ATTRIBUTE",
joinColumns = { #JoinColumn(name = "LIBRARY_ITEM_ID", nullable =false)},
inverseJoinColumns = { #JoinColumn(name="LIBRARY_ITEM_ATTRIBUTE_ID", nullable = false)})
private Set<LibraryItemAttribute> libraryItemAttributes = new HashSet<>();
}
LibraryImage:
#Entity
#Table(name = "library_image", uniqueConstraints = {
})
public class LibraryImage {
#Id
#GeneratedValue(strategy = IDENTITY)
#Column(name = "LIBRARY_IMAGE_ID", unique = true, nullable = false)
private Integer libraryImageId;
#Column(name = "IMAGE_LOCATION")
private String imageLocation;
#Column(name = "IMAGE_TITLE")
private String imageTitle;
#Enumerated(EnumType.STRING)
private LibraryImageType imageType;
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name="LIBRARY_ITEM_ID", nullable = false)
private LibraryItemModel libraryItemModel;
}
Library Attribute:
#Entity
#Table(name = "library_item_attribute", uniqueConstraints = {
})
public class LibraryItemAttribute {
#Id
#GeneratedValue(strategy = IDENTITY)
#Column(name = "LIBRARY_ITEM_ATTRIBUTE_ID", unique = true, nullable = false)
private Integer libraryItemAttributeId;
#Column(name = "ATTRIBUTE_NAME")
private String attributeName;
#Column(name = "ATTRIBUTE_VALUE")
private String attributeValue;
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name="LIBRARY_ITEM_ID", nullable = false)
private LibraryItemModel libraryItemModel;
}
This is really frustrating as the LibraryImage class is mapped without problems and doesn't throw any errors, but the LibraryAttribute class which is annotated in an identical way to the LibraryImage class is throwing this error.
Can someone please have a look and let me know what my problem is?
Found the problem.
In the LibraryItemModel class I defined the Join table with the LibraryItemAttribute to be called "LIBRARY_ITEM_ATTRIBUTE", which is the name of the table of the Library item attributes.
The join table is a different table and should have a different table name.
For the Library Image table above, the image table is called library_image, while the join table is called LIBRARY_ITEM_IMAGE
I have the following model that I need to annotate using JPA:
Merchant(merchant_id, ...).
MerchantType(id1, id2, ...)
MerchantMerchantTypeAssociationTable(merchant_id, id1, id2)
I cannot figure out how to map the association table. Mapping Merchant is straitghtforward, so I will leave it outside of the mappings. The other mappings are as follows:
MerchantType:
#Entity
class MerchantType {
#EmbeddedId
#AttributeOverrides({
#AttributeOverride(name = "e1_id", column=#Column(name="e1_id")),
#AttributeOverride(name = "another_id", column=#Column(name="another_id"))
})
MerchantTypePk id;
#ManyToOne
#JoinColumn(name = "e1_id", referencedColumnName = "e1_id", insertable = false, nullable = false)
#MapsId("e1_id")
AnotherEntity1 e1;
#Column(name = "another_id", referencedColumnName = "another_id", insertable = false, nullable = false)
Long anotherId;
//Two other local fields irrelevant to the discussion here
public MerchantType(){
this.id = new MerchantTypePk();
}
//Getters and setters here.
}
//MerchantTypePk is a simple Embeddable class here below with two Long fields:
//e1_id and another_id
MerchantMerchantTypeAssociation:
#Entity
class MerchantMerchantTypeAssociation {
#EmbeddedId
#AttributeOverrides({
#AttributeOverride(name = "e1_id", column = #Column(name = "e1_id")),
#AttributeOverride(name = "another_id", column = #Column(name = "another_id"))
#AttributeOverride(name = "offer_id", column = #Column(name = "merchant_id"))
})
private MerchantMerchantTypeAssociationPk id;
//******** HERE IS THE QUESTION
//******** HERE IS THE QUESTION
//******** HERE IS THE QUESTION
#ManyToOne
#JoinColumns({
#JoinColumn(name = "e1_id", referencedColumnName = "e1_id", insertable = false, updatable = false),
#JoinColumn(name = "another_id", referencedColumnName = "another_id", insertable = false, updatable = false)
})
#MapsId("e1_id")
#MapsId("another_id")
private MerchantType merchantType;
//Similar mapping to the one above, but with only one Join Column
private Merchant merchant;
//One more local field that is irrelevant to the mapping
//but is the one that is forcing me to map a many - to - many relationship
//in this way.
}
//MerchantMerchantTypeAssociationPk as a simple embeddable
Question: How can I make a mapping for this kind of entities when the annotation '#MapsId' cannot be repeated and it does not accept more than one value?
You did not include the code for MerchantMerchantTypeAssociationPk, but I'm guessing it looks like this:
#Embeddable
public class MerchantMerchantTypeAssociationPk {
public MerchantPk merchantPK;
public MerchantTypePk merchantTypePK;
}
#MapsId is used to specify the attribute within the composite key to which the relationship attribute corresponds, not the columns. So MerchantMerchantTypeAssociation should look like this:
#Entity class MerchantMerchantTypeAssociation {
#EmbeddedId
private MerchantMerchantTypeAssociationPk id;
#ManyToOne
#JoinColumns({
#JoinColumn(name = "e1_id", referencedColumnName = "e1_id",...),
#JoinColumn(name = "e2_id", referencedColumnName = "e2_id",...)
})
#MapsId("merchantTypePK") // <<< *attribute* in Embeddable
private MerchantType merchantType;
#ManyToOne
#JoinColumn(name = "m_id", referencedColumnName = "merchant_id",...)
#MapsId("merchantPK") // <<< *attribute* in Embeddable
private Merchant merchant;
}
Derived identities are discussed in the JPA 2.1 spec, section 2.4.1.
Given the following entity (some columns omitted from this long definition for brevity):
#Table(name = "Products")
public class Products implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#Basic(optional = false)
#Column(name = "SKU")
private String sku;
#Basic(optional = false)
#Column(name = "ProductName")
private String productName;
private boolean allowPreOrder;
#ManyToMany(mappedBy = "productsCollection")
private Collection<Categories> categoriesCollection;
#JoinTable(name = "Products_CrossSell", joinColumns = {
#JoinColumn(name = "SKU", referencedColumnName = "SKU")}, inverseJoinColumns = {
#JoinColumn(name = "CrossSKU", referencedColumnName = "SKU")})
#ManyToMany
private Collection<Products> productsCollection;
#ManyToMany(mappedBy = "productsCollection")
private Collection<Products> productsCollection1;
#JoinTable(name = "Products_Related", joinColumns = {
#JoinColumn(name = "SKU", referencedColumnName = "SKU")}, inverseJoinColumns = {
#JoinColumn(name = "RelatedSKU", referencedColumnName = "SKU")})
#ManyToMany
private Collection<Products> productsCollection2;
#ManyToMany(mappedBy = "productsCollection2")
private Collection<Products> productsCollection3;
How do I get the set of related products for a given product SKU?
The products_related table looks like this:
I know how to get the answer using SQL but I'm new to JPA so I haven't quite grokked the API and query syntax yet.
It seems to me there are some unnecessary collections defined. Anyway:
#JoinTable(name = "Products_Related", joinColumns = {
#JoinColumn(name = "SKU", referencedColumnName = "SKU")}, inverseJoinColumns = {
#JoinColumn(name = "RelatedSKU", referencedColumnName = "SKU")})
#ManyToMany
private Collection<Products> productsCollection2;
This piece (it is present in your code) should give you the desired products. Just rename it to relatedProducts, and the respective setter/getter.
Update: You can get the object by:
Product p = entityManager.find(Product.class, yourProductId);
p.getRelatedProducts();
Obtaining the entity manager depends on your setup, and a better place to look for how to obtain it, is a tutorial.