I have a transactional entity associated to another entity whereby the associated should not be updated in an case.
Eg. Case *-> User
Where a Case is owned by a User and reversely a User can have many associated Case.
The association is mapped using OneToMany and JoinColumn JPA annotations.
I have also tried marking the Trasactional annotation for User entity as readonly and also made the fetch methods Transient. But this doesnot seem to stop update on User if its state is changed.
Please help me a figure a way to declare a "read-only" association to User.
You can add updatable=falseon #JoinColumn annotation.
Furthermore you should not add a setter method for user in your Case entity and same for caseSet in your User entity. The getter getCaseSet in User entity should also return an unmodifiable collection:
public Set<Case> getCaseSet() {
return Collections.unmodifiableSet(caseSet);
}
The Column annotation and XML element defines insertable and updatable options. These allow for this column, or foreign key field to be omitted from the SQL INSERT or UPDATE statement. These can be used if constraints on the table prevent insert or update operations. They can also be used if multiple attributes map to the same database column, such as with a foreign key field through a ManyToOne and Id or Basic mapping. Setting both insertable and updatable to false, effectively mark the attribute as read-only.
In #OneToMany mapping, #JoinColumn annotation, add both updatable=false and insertable=false, then specify the cascade type as PERSIST instead of ALL
#OneToMany(cascade = CascadeType.PERSIST)
#JoinColumn(name = "<ReadOnlyTableName>", updatable = false, insertable = false)
Related
I have a problem with using a OneToMany-Mapping with Hibernate that was working in version 4.3.8.Final but is not with version 5.4.2.Final .
When I query multiple entities from the db that have the same entries in a list that is mapped with OneToMany and then try to update those entities, hibernate throws the following exception even though I do not update any entries from the mapped relation: "Found shared reference to a collection: de.Artikel.filialeLager; nested exception is org.hibernate.HibernateException: Found shared reference to a collection: de.Artikel.filialeLager"
Here is my mapping, that was working fine with version 4.3.8.Final of Hibernate but is not anymore with 5.4.2.Final.:
#OneToMany(fetch = LAZY)
#JoinColumn(name = "SOME_ID", referencedColumnName="SOME_ID", insertable = false, updatable = false)
private List<filialeLager> filialeLager;
It seems to have a unidirectional relationship but is adding a reference column for a two-way relationship
The name of the column referenced by this foreign key column. When
used with entity relationship mappings other than the cases described
below, 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 Join- Table 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 collection table
mapping, the referenced column is in the table of the entity
containing the collection.
You should have something similar to this:
#OneToMany(fetch = LAZY)
#JoinColumn(name = "SOME_ID", insertable = false, updatable = false)
private List<filialeLager> filialeLager;
I am mapping some Java classes using hibernate on a database that I have no write access for. One of the fields used as a FK between ClientEpisodes and Physician's has 6 rows that contain a -1 for the FK. THis is obviously an invalid FK, but I need to still join and simply ignore these Physicians and have a null physician.
I am joining the class using
#JoinColumn(name = "epi_phid1", referencedColumnName = "ph_id", foreignKey = #ForeignKey(ConstraintMode.NO_CONSTRAINT))
private Physician physician;
I tried specifying NO_CONSTRAINT to see if it would ignore it then, but even still I get the following error:
javax.persistence.EntityNotFoundException: Unable to find private.package.info.Physician with id -1
Is there any way to tell Hibernate to ignore values that aren't valid such as the -1?
The #ForeignKey annotation with NO_CONSTRAINT value tells hibernate to not generate foreign keys, if schema generation is used. It doesn't have any effect on the internal entity validation in the JPA framework.
There is a hibernate specific #NotFound annotation which you could use:
#JoinColumn(name = "epi_phid1", referencedColumnName = "ph_id")
#NotFound(action = NotFoundAction.IGNORE)
private Physician physician;
However be advised that if you use this in a #OneToMany or #ManyToMany annotation which maps a Collection, hibernate will fill the invalid/missing entities with null (so the list will contain null value(s)).
I am using Hibernate as my JPA provider, and I want one of the fields in an entity to be ignored when calling save(). However, I do have a matching column in the corresponding database table and I want my entity field to be populated with the database value when I fetch the entity. So, I want the field to be ignored when saving the entity, but not when fetching it.
If I use #Transient, the field is completely ignored, which is not what I want. Is there any way to do this?
From the excellent book Pro JPA 2 :
JPA defines options to set individual mappings to be read-only using
the insertable and updatable elements of the #Column and #JoinColumn
annotations. These two settings default to true but can be set to
false if we want to ensure that the provider will not insert or update
information in the table in response to changes in the entity
instance. If the data in the mapped table already exists and we want
to ensure that it will not be modified at runtime, then the
insertable and updatable elements can be set to false, effectively
preventing the provider from doing anything other than reading the
entity from the database.
#Column(insertable = false, updatable = false)
private String readOnlyField;
I have a JPA Entity that has an attribute declared in the following way
#OneToOne(cascade = CascadeType.MERGE, fetch = FetchType.EAGER)
#JoinColumn(name = "userId", referencedColumnName = "id", insertable = false, updatable = false)
private UserBare user;
(UserBare is a dummy entity I've created which is a dumbed down version of a User obj as I needed some date, not all of User obj be made available to this entity. Is there a better way to approach this?
This is a convenience attr that I use just make the userBare object available to this entity when reading this entity. But when I actually write this entity, it seems to create new entries of 'user' in the database (instead of updating). I already have insertable=false,updatable=false but it still writes to the database. I tried removing the CascadeType declaration but that is throwing an error.
Here is the database snapshot after the unwanted rows are added (last 3). Also I've noticed that deleting the original entity did not delete these three unwanted rows. So I guess JPA is storing them but the references are intact to the original entity.
My souspicioun would be that "OneToOne" means "OneToOne" excluding the possibility of "OneToZero" if you don't set Optional to true like this:
#OneToOne(optional=true)
But just a guess.. I'm not sure
I have seen a couple of examples on the Internet about using JoinColumn like the way in the example below.
Actually, there are two questions I want to ask you about this partcular example. Can't we just get rid of the "optional" parameter by adding a "nullable=false" parameter to the JoinColumn. Are there any differences between optional and nullable entity relationship-wise?. What are the advantages of setting insertable and updatable to false in the joincolumn? Is this done to ensure that Employee entity cannot update the Department entity?
#Entity
public class Employee {
// ...
#ManyToOne(optional=false)
#JoinColumn(name="DEPT_ID", insertable=false, updatable=false)
private Department department;
// ...
}
optional = false on the ManyToOne is a runtime instruction for the persistence framework to interpret when building java objects. nullable = true on the JoinColumn is for setting up the database schema and may or may not be interpreted at runtime depending on your persistence provider.
Normally that JoinColumn mapping is done that way to indicate that the relationship is managed from the other side, by the Department.
You would likely have:
#OneToMany(cascade=CascadeType.ALL)
#JoinColumn(name="DEPT_ID")
private Set<Employee> employees;
Over on your department, and you'd create new employee-department relationships by adding them to the collection there, rather than setting a Department on the Employee. That's why you mark the Employee's department as non-updatable, because the Department "owns" the ability to modify the relationship.