Initial Situation:
I have these two entities, GroceriesList and Product.
GroceriesList:
A GroceriesList can have several products.
#Entity
#Table(name = "lists")
public class GroceriesList {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "list_id")
private Long listId;
#Column(name = "list_name")
private String listName;
#ManyToMany(cascade = CascadeType.MERGE)
#JoinTable(name = "lists_products",
joinColumns = #JoinColumn(name = "product_id", referencedColumnName = "list_id"),
inverseJoinColumns = #JoinColumn(name = "list_id", referencedColumnName = "product_id")
)
private Set<Product> products;
}
Products:
A Product can be allocated to several GroceriesLists
#Entity
#Table(name = "products")
public class Product {
public enum Category {
Dairy,
Fruit,
Vegetable,
Meat,
Grains
}
// Product ID Column, GenerationType.Identity refers to auto incr in Postgres
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "product_id")
private Long productId;
#Column(name = "product_name")
private String productName;
#Column(name = "product_vendor")
private String productVendor;
#Enumerated(EnumType.STRING)
#Column(name = "product_category")
private Category productCategory;
#Column(name = "product_storedquantity")
private Integer productStoredQuantity;
#JsonIgnore
#ManyToMany(mappedBy = "products")
private List<GroceriesList> groceriesLists;
}
The entities and relationships are stored in three different tables in Postgres(One for Lists, one for products, and one mapping table for the relationships).
The mapping table:
Mapping Table "lists_products"
A sample Product:
Sample Product with Id=4
The problem: I'm trying to create new lists, and that works. However, as you can spot from the Mapping Table Image, Hibernate inserts the IDs into the wrong columns. The list_id in the mapping table is currently getting the product_id, and the product_id in the mapping table is getting the list_id.
I have tried to change the order of column names & references in the #JoinTable annotation in the GroceriesList Entity. However, that throws a mapping Error. I assume my error lies somewhere in that annotation. Interestingly, Hibernate uses the correct SQL-Query. What am I missing here?
After consulting fladdimir's solution, it gave me an idea and I solved my issue. The problem lied within the #JoinColumn annotation, where I thought the "name = ..." property refers to the column name in the database.
#ManyToMany(cascade = CascadeType.MERGE)
#JoinTable(name = "lists_products",
joinColumns = #JoinColumn(name = "product_id", referencedColumnName = "list_id"),
inverseJoinColumns = #JoinColumn(name = "list_id", referencedColumnName = "product_id")
)
private Set<Product> products;
However, that property refers to the declared variable inside the Entity in Spring Boot, i.e. listId
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "list_id")
private Long listId;
So, the working implementation of the #JoinTable Annotation should look like the following, where "name = ..." uses that variable name:
#ManyToMany(cascade = CascadeType.MERGE)
#JoinTable(name = "lists_products",
joinColumns = #JoinColumn(name = "listId", referencedColumnName = "list_id"),
inverseJoinColumns = #JoinColumn(name = "productId", referencedColumnName = "product_id")
)
private Set<Product> products;
Related
I want to join these 3 Tables.
Here you see my Person Entity
#Entity
#Table(name = "Person", schema = "public")
public class PatientEntity {
#Id
#Column(name = "id")
private Long id;
#Column(name = "lastname")
private String name;
#OneToMany
#JoinTable(name = "person_contact", joinColumns = { #JoinColumn(name = "person_id") }, inverseJoinColumns = { #JoinColumn(referencedColumnName = "id") })
#Column(name = "contact")
private Set<ContactEntity> contacts;
//Getter Setters
And here is my contact entity:
#Entity
#Table(name="contact",schema="public")
public class ContactEntity {
#Id
#Column(name="id")
private Long id;
#Column(name="phone")
private String phone;
//Getter Setters
I just read the Persons from the Table with findById with a Spring JPARepository, but there is no Contact mapped. There is no error during my HTTP request, but instead of a Contact there is null and this error message:
com.sun.jdi.InvocationException occurred invoking method.
The business case is, that every Person can have one or more contact. Is it possible to make it with JPA Annotations or do I need to map it by myself with a JPQL? Or should I create an Entity for the middle table? (person_contact)
The Database is a PostgreSQL Database.
There is this notification too in the Log:
ERROR: column contacts0_.contacts_id does not exist
Perhaps you meant to reference the column "contacts0_.contact_id".
Position: 306
Your #JoinTable has incorrect #JoinColumn specifications and corresponds to the following ddl.
create table person_contact (person_id bigint not null, contacts_id bigint not null, primary key (person_id, contacts_id))
To map your db structure, use following (note removed #Column annotation)
#OneToMany
#JoinTable(name = "person_contact", joinColumns =
{
#JoinColumn(name = "person_id", referencedColumnName = "id"),
},
inverseJoinColumns = {
#JoinColumn(name = "contact_id", referencedColumnName = "id")
})
private Set<ContactEntity> contacts;
I also encourage you to read https://vladmihalcea.com/the-best-way-to-map-a-onetomany-association-with-jpa-and-hibernate/ and reconsider a db structure without a join table (depending on your load and the effort to make this db change)
I have 3 entities User, Order, Item with a mapping like this:
#Entity
public class Item {
#Id
#Access(AccessType.PROPERTY)
private long id; // item id predefined
//..getters and setters
}
#Entity
public class Client {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
//...getters and setters
}
#Entity
public class Order {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(nullable = false)
#Access(AccessType.PROPERTY)
private Long id;
#ManyToOne(optional = false, fetch = FetchType.LAZY, cascade = {
CascadeType.PERSIST, CascadeType.MERGE,
CascadeType.REFRESH, CascadeType.DETACH
})// without removing
//#JoinColumn(name = "client_id") - works fine
#JoinTable(name = "client_cr_order_cr_item",
joinColumns = #JoinColumn(name = "order_id"),
inverseJoinColumns = #JoinColumn(name = "client_id"))
private Client client;
#NotEmpty
#OneToMany(fetch = FetchType.LAZY, cascade = {
CascadeType.PERSIST, CascadeType.MERGE,
CascadeType.REFRESH, CascadeType.DETACH
})// without removing
#JoinTable(name = "client_cr_order_cr_item",
joinColumns = #JoinColumn(name = "order_id"),
inverseJoinColumns = #JoinColumn(name = "item_id"))
private List<Item> items;
//...getters and setters
}
When I persist order it fails with error:
ERROR: null value in column "item_id" violates not-null constraint
it generate query like this:
insert into client_cr_order_cr_item (client_id, order_id) values ()
i.e. it do not fill out segment_id field by some reason I don't know. But I refer to client not thru 3th table but using FK #JoinColumn(name = "client_id") , then it generate correct query:
insert into order_cr_item (order_id, item_id) values ()
Please, could you explain this behavior? Why mapping of client affect items? Is there any hint to make hibernate persists items to 3th table?
I have 3 tables in my database, container, item and item_container which is a join_table of many to one between container and item. Entities in code are mapped using 2 classes: Container and Item.
The relation is unidrectional from Container to Item.
join_table in hibernate is mapped only by annotations in Container class.
#Entity
#Table(name="container")
public class Container {
#Id
#Column(name = "container_id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
#JoinTable(name = "item_container",
joinColumns = #JoinColumn(name = "container_id"),
inverseJoinColumns = #JoinColumn(name = "item_id"))
private Set<Item> items;
//getter/setters
}
My problem is: when i have the type of collection Set<Item> items changed to List<Item>, the list contain every Item entity twice. I cant find the reason why, the hashCode and equals methods of Item are based only on the item_id field.
UPDATE:
Code for Item class:
#Entity
#Table(name = "item")
#Inheritance(strategy=InheritanceType.SINGLE_TABLE)
public class Item {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "item_id")
private Long id;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "item_template_id", nullable = false)
private ItemTemplate itemTemplate;
#Column(name = "item_group")
#Enumerated(EnumType.STRING)
private ItemGroup itemGroup;
#Column(name = "amount")
private int amount;
//getter/setters
}
Why Hibernate tries to insert new record with existing id?
Category table before save (was filled manually with insert)
ID | NAME | IMAGE
1 | 'NAME'| 'IMAGE'
Save code
//Category{id=0, name='NAME', image='IMAGE', parent=null}
getCurrentSession().save(category);
Should be inserted with id 2.
Category Java code
#Entity
#Table(name = "CATEGORY",
indexes = {
#Index(name = "CATEGORY_NAME_INDEX",
columnList = "CATEGORY_NAME")})
public class Category implements NamedModel {
#Id
#Column(name = "CATEGORY_ID")
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#NotNull
#Size(min = 1, max = 256)
#Column(name = "CATEGORY_NAME", length = 256)
private String name;
#OneToOne(fetch = FetchType.EAGER)
#JoinTable(name = "CATEGORY_RELATIONS",
joinColumns = {
#JoinColumn(name = "CATEGORY_RELATIONS_CATEGORY_ID",
referencedColumnName = "CATEGORY_ID")},
inverseJoinColumns = {
#JoinColumn(name = "CATEGORY_RELATIONS_PARENT_ID",
referencedColumnName = "CATEGORY_ID")})
private Category parent;
#OneToMany(cascade = {CascadeType.REMOVE, CascadeType.PERSIST},
fetch = FetchType.LAZY, mappedBy = "parent")
private List<Category> children;
}
SOLUTION
//Category
#GeneratedValue(strategy = GenerationType.IDENTITY)
//CategoryRelations
#Entity
#IdClass(CategoryRelationsPrimaryKey.class)
public static class CategoryRelationsPrimaryKey implements Serializable {
private Long categoryId;
private Long parentId;
instead of long.
This is because you had deleted/added a record from database directly instead from the application i.e. ORM, that's why values in hibernate_sequence is no longer maintained.
Hibernate maintains values in a hibernate_sequence table which would be inserted on creating a new record.
update next_val column value in hibernate_sequence to resolve the problem.
You can use Annotation #GeneratedValue(strategy = GenerationType.IDENTITY) to delegate primary key generation to database.
I'm trying to create a join table with #JoinTable from 3 different entities. Below is the code sample I'm using. While creating join table I'm getting below error. Please help to resolve.
There are 3 entities in my design. Credential, Category and Tenant.
Now I'm trying to make a join table that will contain the pk of these 3 tables using #ManyToMany annotation between them. Below is the relationship which I'm trying to make.
#Entity
#Table(name = "CREDENTIALS")
public class CredentialsEntity {
/** The credential id. */
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "ID")
private int credentialId;
#ManyToMany(cascade={CascadeType.PERSIST, CascadeType.MERGE})
#JoinTable(name = "CATEGORY_HAS_CREDENTIALS",
joinColumns = {
#JoinColumn(table="CATEGORY", name = "CATEGORY_ID", referencedColumnName = "ID"),
#JoinColumn(table ="TENANT", name = "TENANT_ID", referencedColumnName = "ID")},
inverseJoinColumns = #JoinColumn(table="CREDENTIALS", name = "CREDENTIAL_ID", referencedColumnName = "ID"))
private List<TenantEntity> tenantEntities;
}
==========================
#Entity
#Table(name = "TENANT")
public class TenantEntity {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "ID")
private int tenantId;
#ManyToMany(mappedBy = "tenantEntities", cascade = CascadeType.ALL)
private List<CredentialsEntity> credentialsEntities;
}
==========================
#Entity
#Table(name = "CATEGORY")
public class NodeCategory {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID")
private int categoryId;
#ManyToMany(cascade = CascadeType.ALL)
private List<CredentialsEntity> credentialsEntities;
}
Caused by:
org.hibernate.AnnotationException: Cannot find the expected secondary
table: no TENANT available for
com.aricent.aricloud.entity.CredentialsEntity at
org.hibernate.cfg.Ejb3Column.getJoin(Ejb3Column.java:363) at
org.hibernate.cfg.Ejb3Column.getTable(Ejb3Column.java:342) at
org.hibernate.cfg.Ejb3Column.checkPropertyConsistency(Ejb3Column.java:584)
at
org.hibernate.cfg.annotations.CollectionBinder.buildCollectionKey(CollectionBinder.java:1018)
at
org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1336)
EDIT
I'm able to do the jointable like below, as mentioned in link
is this correct approach or I'm doing something wrong?
#ManyToMany(cascade={CascadeType.ALL})
#JoinTable(name = "CATEGORY_HAS_CREDENTIALS",
joinColumns = {
#JoinColumn(name = "CREDENTIAL_ID", referencedColumnName = "ID")},
inverseJoinColumns = #JoinColumn(table = "CATEGORY", name = "CATEGORY_ID", referencedColumnName = "ID"))
#MapKeyJoinColumn(name = "TENANT_ID", referencedColumnName ="ID")
#ElementCollection
private Map<TenantEntity, NodeCategory> tenantCategoryMap = new HashMap<TenantEntity, NodeCategory>();