2 entities that I have: Country and User
#Entity(name = "Country")
#Table(name = "countries")
public class Country {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#OneToMany(cascade = CascadeType.ALL,
orphanRemoval = true)
private List<User> users = new ArrayList<>();
}
#Entity(name = "User")
#Table(name = "users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private boolean removed;
}
Entity User has an attribute, removedtype boolean and we need to skip/ignore all User's that have removed equals true.
Does Hibernate provide any suitable mechanism to achieving my goal?
P.S: Google says that potentially I can use annotations like: #JoinColumn, #JoinColumnOrFormula, but based on docs that I have read, annotations mentioned above belong to #ManyToOne scenario, in my particular case I have #OneToMany relation.
With hibernate, using #Where on the entity should do the trick. This will prevent any user to be loaded which has the removed flag set to true. You might find more information in the hibernate docs
If you only want this to be on the collection, you can add the annotation on the relationship
#Entity(name = "Country")
#Table(name = "countries")
public class Country {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#OneToMany(cascade = CascadeType.ALL,
orphanRemoval = true)
#Where( clause = "removed = false" ) // <- here
private List<User> users = new ArrayList<>();
}
Alternatively, if you don't want to load any removed user at all, the annotation can be added to the class.
#Entity(name = "User")
#Table(name = "users")
#Where( clause = "removed = false" ) // <- here
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private boolean removed;
}
A word of caution, I haven't used this, but I assume that if you have other entities with linked to a user which has the flag set to true, you'll need to update the annotations to allow nulls.
For example, imagine an ecomerce site, an Order is linked to a user. Loading an Order linked to a removed user will fail, or you can ammend the annotations so it returns an order with a null user. I hope this makes sense!
Related
I have yet another #OneToMany question. In this case, I'm trying to model a person having a list of excluded people they shouldn't be able to send items to. This is a Spring Boot app using JPA.
In the code below, the exclusions list populates properly but the excludedBy List does not. Because of this, I believe that is causing the deletion of a Person that is excluded by another person to fail because the Exclusion in excludedBy is not mapped on the object properly.
#Entity
#Table(name = "person")
public class Person {
#Id
#GeneratedValue
#Column(nullable = false)
Long id;
...
#OneToMany(mappedBy = "sender", cascade = { CascadeType.ALL })
List<Exclusion> exclusions = new ArrayList<>();
//This is not getting populated
#JsonIgnore
#OneToMany(mappedBy = "receiver", cascade = { CascadeType.ALL })
List<Exclusion> excludedBy = new ArrayList<>();
...
}
#Entity
#Table(name = "exclusions")
public class Exclusion {
#Id
#GeneratedValue
#Column(nullable = false)
Long id;
#ManyToOne
#JsonIgnore
Person sender;
#ManyToOne
Person receiver;
...
}
I would expect that this would have mapped the bidirectional relationship properly and as such the excludedBy List would be populated as well.
Any wisdom on this matter would be great!
1 - An #Id is by default not nullable, not required:
#Column(nullable = false)
2 - There is no need for an #Id in this class. Both sides of the exclusion are together unique. Not needed:
#Id
#GeneratedValue
Long id;
3 - An "Exclusion" requires both an excludedBy and an excluded, give them names that match and they are your #Id. It is a 2 way ManyToMany relationship.
#Entity
#Table(name = "exclusions")
public class Exclusion {
#Id
#ManyToMany // An ID so not optional, so no need for (optional = false)
Person excludedBy;
#Id
#ManyToMany // An ID so not optional, so no need for (optional = false)
Person excluded;
}
Entity Exclusion always knows both sides of the story.
#ManyToMany(mappedBy = "excludedBy", cascade = { CascadeType.ALL })
List<Exclusion> excluded = new ArrayList<>();
#ManyToMany(mappedBy = "excluded", cascade = { CascadeType.ALL })
List<Exclusion> excludedBy = new ArrayList<>();
Tip: JSON DTOs shouldn't be defined in your JPA DTOs, otherwise you can't change your internal data model independently of your external API model.
I had this problem in the past. Your key problem ist that your ORM Mapper hibernate does not know which of your database entries need to be assinged to exclusions and which are assiged to excludedBy. You need a discriminator and add the constraint in your select. I would propose a solution that looks something like this:
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "PRIMARY_KEX_IN_EXCLUSION_TABLE", referencedColumnName = "id")
#Where(clause = "is_excluded_by = 0")
private Set<Exclusion> exclusions;
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "PRIMARY_KEX_IN_EXCLUSION_TABLE", referencedColumnName = "id")
#Where(clause = "is_excluded_by = 1")
private Set<Exclusion> excludedBy;
the value isExcludedBy needs to be a database column, part of your Entity and set in your code manually.
I think you also need to use Set instead of List when having multiple collections in one Entity. https://vladmihalcea.com/spring-data-jpa-multiplebagfetchexception/
My two entities have one to one relation
#Getter
#Setter
#Entity
#NoArgsConstructor
#AllArgsConstructor
#Builder(toBuilder = true)
#Table(uniqueConstraints = #UniqueConstraint(columnNames = "email"), name = "library_user")
public class AppUser {
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
#EqualsAndHashCode.Exclude
private Long id;
// other fields
#OneToOne(mappedBy="user", cascade={CascadeType.REMOVE,CascadeType.PERSIST}, orphanRemoval = true)
private PasswordResetToken token;
// getters/setters and equals/hashcode
}
#Getter
#Setter
#Entity
#NoArgsConstructor
#AllArgsConstructor
#Builder(toBuilder = true)
#Table(name = "password_reset_token")
public class PasswordResetToken {
private static final int EXPIRATION = 60 * 24;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
// other fields
#OneToOne(targetEntity = AppUser.class, fetch = FetchType.EAGER, cascade={CascadeType.REMOVE,CascadeType.PERSIST}, orphanRemoval = true)
#JoinColumn(nullable = false, name = "user_id")
private AppUser user;
// getters/setters and equals/hashcode
I tried to delete my user entity by this method
public void deleteUser(Long id) {
resetTokenRepository.deleteAllByUserId(id);
userRepository.deleteById(id);
}
PasswordResetTokenRepository class which method I called in my service method, for deleting user I used regular hibernate method deleteById(Long id)
#Repository
public interface PasswordResetTokenRepository extends JpaRepository<PasswordResetToken, Long> {
void deleteAllByUserId(Long id);
}
But when I try to delete by this method I got this error:
not-null property references a null or transient value : kpi.diploma.ovcharenko.entity.user.PasswordResetToken.user
I read several websites how to delete one to one relation, but their advices didn't help me. For example, I tried a lot of variants of annotation cascade={CascadeType.ALL}, tried all the variants(CascadeType.REMOVE,CascadeType.PERSIST and so on), all time I got the same error. Help me pls, to understand what I do wrong.
try this:
#OneToOne(cascade = CascadeType.REMOVE, orphanRemoval = true)
Here is complete explication .
I have 4 Entities, that a related to each other with #OneToMany relationships.
When I try to save Order that contains OrderItem - Orderitem has no backreference.
In the code below only important fields are showed for brevity ( usual strings and primitives are omitted ). I decided to include Dish and User Entities also.
Order:
#Entity
#NoArgsConstructor
#Getter
#Setter
#ToString
public class Order {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#ManyToOne(fetch = FetchType.LAZY)
private User user;
#OnDelete(action = OnDeleteAction.CASCADE)
#OneToMany(
mappedBy = "order",
cascade = CascadeType.ALL,
fetch = FetchType.EAGER,
orphanRemoval = true)
private List < OrderItem > orderItems;
}
Dish:
#Entity
#NoArgsConstructor
#Getter
#Setter
#ToString
public class Dish {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#OneToMany(cascade = CascadeType.ALL,
fetch = FetchType.LAZY,
mappedBy = "dish")
#ToString.Exclude
private List < OrderItem > orderItems;
}
OrderItem:
#Entity
#NoArgsConstructor
#Getter
#Setter
#ToString
public class OrderItem {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#ManyToOne(fetch = FetchType.LAZY)
#ToString.Exclude
private Dish dish;
#ManyToOne(fetch = FetchType.LAZY)
private Order order;
private int quantity;
}
User:
#Entity
#NoArgsConstructor
#Getter
#Setter
#ToString
#Table(name = "users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#OneToMany(
mappedBy = "user",
cascade = CascadeType.ALL,
orphanRemoval = true
)
private List < Order > orders;
}
The problem happens when I try to save Order with Spring data JPA.
Let's print Order to see OrderItem before saving.
public Order saveOrder(Order order) {
System.out.println("SERVICE saving order " + order);
return orderRepository.save(order);
}
As you can see, orderItems backreference is null before saving ( I though spring data jpa should deal with setting it ).
SERVICE saving order Order(id=0,
orderItems=[OrderItem(id=0, quantity=2, order=null)])
Here is what I have in DB ( Order and OrderItem entities ).
In your OrderItem class, add annotation below:
#ManyToOne(cascade = {CascadeType.DETACH, CascadeType.MERGE, CascadeType.REFRESH, CascadeType.PERSIST}, fetch=FetchType.LAZY)
#JoinColumn(name="order_id", referencedColumnName="id", nullable = false)
Order order.
One more thing, I suggest you use SEQUENCE_GENERATOR, beacause IDENTITY means: I'll create the entity with a null ID and the database will generate one for me. I don't think Postgres even supports that, and even if it does, a sequence generator is a better, more efficient choice.
The best option that I found for this is doing something like:
order.getOrderItems().forEach(orderItem -> orderItem.setOrder(order));
Before your save() call. Even though order is not persisted at this point, it seems like Hibernate can resolve the relation and the back references will be set correctly.
If you do not want to bother setting the back reference in your business logic, you can add something like this to your entity:
class Order {
...
#PrePersist
public void prePersist() {
setMissingBackReferences();
}
private void setMissingBackReferences() {
orderItems.forEach(oderItem -> {
if (oderItem.getOrder() == null) {
oderItem.setOrder(this);
}
});
}
...
}
I have a one to many relation on post class, and on the relation table I have one to one relation with user. Everything works find, but i want to be able to remove the relation, keeping the user entity, is that possible?
At this moment with the annotation orphanRemoval = true when I remove from post Detail list an element, this its removed from post_details table but the user is removed too.
#Entity
#Table(name = "ta_post")
public class Post{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private Date fcDate;
#OneToMany(mappedBy="post", cascade=CascadeType.ALL, orphanRemoval = true)
private List<PostDetails>;
}
#Entity
#Table(name = "ta_user")
public class User{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private int mail;
}
#Entity
#Table(name = "ta_post_details")
public class PostDetails{
private int id;
#ManyToOne
#JoinColumn(name="post_id")
private Post post;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name="user_id")
private User user;
private String postComments;
}
You must remove the CascadeType.ALL from the PostDetails. If you want to be able to change the User through the PostDetails, you can set the CascadeType to PERSIST or MERGE. If you want to create a PostDetail along with an User, you need to include the CascadeType CREATE.
I'd guess you are creating the user somewhere else and you just associate one with a Post, so removing the CascadeType.ALL should be enough to not delete your User from the database.
I already asked about my situation and didn't find a proper solution. After some additional search I think I know the source problem although don't know how to resolve it. As mentioned I have:
#Table(name = "role__parent")
#IdClass(RoleAssociationKey.class)
#Data
public class RoleAssociation implements Serializable {
#Id
#JoinColumn(name = "has_parent_role_id")
private Role node;
#Id
#JoinColumn(name = "is_parent_for_role_id")
private Role parent;
...
}
#Data
class RoleAssociationKey implements Serializable {
private static final long serialVersionUID = 1L;
private int node;
private int parent;
}
and I have
#Table(name = "role")
#Data
public class Role implements IRole {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#OneToMany(mappedBy = "node", orphanRemoval = true, cascade = { CascadeType.ALL })
private List<RoleAssociation> parentRoles;
...
Up to this point I think nothing special. I have the query:
#NamedQuery(name = "Role.findParents", query =
"SELECT r FROM Role r JOIN RoleAssociation ra ON r.id = ra.parent.id WHERE ra.node.id = :id")
with the purpose to all set parents. When I compile it Hibernate complainsleft and right hand sides of a binary logic operator were incompatible [integer : component[node,parent]]
Since the statement works in EclipseLink I have no clue how to change it into a working Hibernate one. Help would be highly appreciated.
After some struggels I finally figured the root cause of this problem. I'm aware that the SQL might be improved nevertheless I fail at other similar spots.
Hibernate requires to have a matching pair for #OneToMany relation.
In my query I refer to the parent of my role. The solution is
#Data
public class RoleAssociation implements Serializable {
#Id
#JoinColumn(name = "has_parent_role_id")
#ManyToOne // <<<<==== rerequired for Hibernate
private Role node;
#Id
#JoinColumn(name = "is_parent_for_role_id")
#ManyToOne // <<<<==== rerequired for Hibernate
private Role parent;
I have no clue why Hibernate complains while EclipseLink can fetch the required information. Nevertheless with this additional annoation the code works!