hibernate-onetomany | 易学教程

One to Many Relationship in spring boot REST Api

阅读更多关于 One to Many Relationship in spring boot REST Api

问题 I am using spring boot to create a REST API. In this API, I have a One to Many relationship between check-in and Guests . I created a controller for check-in and use that save function of spring JPA. The save method is updating both checkin and guest tables but for the guest table, the check-in foreign key in the guests table is not getting added instead showing as null. Please someone help me. I need to create both guests and checkin simultaneously. Check-in Model @Data @Entity public class

TransientObjectException - object references an unsaved transient instance - save the transient instance before flushing

阅读更多关于 TransientObjectException - object references an unsaved transient instance - save the transient instance before flushing

问题 I've come across a few good possible answers to my questions, but this is regarding an upgrade from Hibernate 3.4.0GA to Hibernate 4.1.8. So this used to work under the previous version and I've searched high and low for why its breaking in this new version. I get a org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.test.server.domain.model.NoteItem.note -> com.test.server.domain.model.Note Any help would

Hibernate performance issue with OneToMany / nullable relationship

阅读更多关于 Hibernate performance issue with OneToMany / nullable relationship

问题 We use @OneToMany for our Parent->Child->Child->Child DB relationship: @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "THE_ID", nullable = false ) private List<ChildClass> children = new ArrayList<ChildClass>(); We have a scenario with a lot of data (100K inserts) where the performance is atrocious (actually times out) when inserting. With a small amount of data (1K inserts) we are however fine. So for no good reason I have removed the nullable = false and changed the DB foreign key

Hibernate @OneToMany Relationship Causes Infinite Loop Or Empty Entries in JSON Result

阅读更多关于 Hibernate @OneToMany Relationship Causes Infinite Loop Or Empty Entries in JSON Result

问题 I have two entities, an entity "movie" and an entity "Clip" each clip belongs to one movie and a movie can have multiple clips. My code looks like: Movie.java @OneToMany(mappedBy = "movie", targetEntity = Clip.class, cascade = CascadeType.ALL, fetch = FetchType.EAGER) private Set<Clip> clips = new HashSet<Clip>(); Clip.java @ManyToOne @JoinColumn(name="movie_id") private Movie movie; The tables are being generated and each Clip has a column "movie_id" but this causes my application to end up

Rather than child is deleting its updating ,when parent is deleted

阅读更多关于 Rather than child is deleting its updating ,when parent is deleted

问题 My problem is when i delete the parent, child is not deleted but instead of deleting child ,child is updating.Parent table is Employee and child table is EmployeeProject there is one-to-many relation ship exist between employee and project one employee had many projects what i have done please check where i m mistaking this is the query is showing on console Hibernate: update employee_project set employeeNumber=null where employeeNumber=? Hibernate: delete from employee where EMPLOYEE_NUMBER=

How to avoid Hibernate generating two queries for an update with OneToMany?

阅读更多关于 How to avoid Hibernate generating two queries for an update with OneToMany?

问题 I'm facing the same situation as in this question, that has no useful answer. When I add a new element to the many part of my one-to-many relation, Hibernate generates two queries, one to insert and one to update the foreign key to the parent. Why does it need the second query for? Isn't the parent's id set in the insert? Is there any way of avoiding this? Hibernate: /* insert mydomain.LanguageKnowledge */ insert into languageKnowledge (language_fk, level_fk, personId_fk) values (?, ?, ?)

n+1 query not working

阅读更多关于 n+1 query not working

问题 In the below code I expect the n+1 query problem to occur, but it's not happening. User.java : import java.util.*; public class User { private long userId; private String firstName; private Set phones; public User() { System.out.println("0-arg constructor :User"); } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public long getUserId() { return userId; } public void setUserId(long userId) { this.userId = userId; }

Hibernate How to correctly delete children in @OneToMany?

阅读更多关于 Hibernate How to correctly delete children in @OneToMany?

问题 I have a very simple unidirectional @OneToMany from a Parent object to a List of children with CascadeType.ALL. How would I correctly remove and delete one of the children? Simply calling remove(child) on the List and then session.saveOrUpdate(parent) of course does not work and the child is not deleted in the database unless I specify orphan removal. As an alternative to orphan removal, would it be correct if I session.delete(child) to delete it in the DB, then remove(child) from the List

How to include join column in json result with JPA+Hibernate

阅读更多关于 How to include join column in json result with JPA+Hibernate

问题 I have a Province class like below: public class Province { @Id Long id; @Column(nullable = false) String name; @JsonManagedReference @OneToMany(mappedBy = "province") List<City> cities; } and a City class like below: public class City{ @Column(nullable = false) String name; @JsonBackReference @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "province_id") Province province; } now I want to have pronivce_id (as an int value not object) in JSON result of City in REST result. How can I do

How to include join column in json result with JPA+Hibernate

阅读更多关于 How to include join column in json result with JPA+Hibernate

I have a Province class like below: public class Province { @Id Long id; @Column(nullable = false) String name; @JsonManagedReference @OneToMany(mappedBy = "province") List<City> cities; } and a City class like below: public class City{ @Column(nullable = false) String name; @JsonBackReference @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "province_id") Province province; } now I want to have pronivce_id (as an int value not object) in JSON result of City in REST result. How can I do this? You can return province_id with JsonIdentityInfo and JsonIdentityReference Jackson annotations.