jpa

问题 I'm making a game with Spring MVC. I have a method for get the game and update but when it goes to update it gives an error, this is the code: HomeController.class @Transactional @RequestMapping(value = "/partida/{idPartida}", method = RequestMethod.GET) public String getPartida(@PathVariable("idPartida") long idPartida, Model model) throws IOException { Partida p = ServicioAplicacionPartida.getPartida(entityManager, idPartida); if (p.getJson() == null) { p.inicializarPartida(entityManager);

问题 I have an existing database table For e.g. T_STUDENTS on top of which I have to create a JPA entity. All three columns in the table are NON NULL and the table has a self-reference as mentor_id id | name | mentor_id -----|---------|---------- 1 | John | 1 -----|---------|---------- 2 | Marc | 1 -----|---------|---------- 3 | Abby | 2 -----|---------|---------- 4 | Jimy | 3 -----|---------|---------- 5 | Boni | 4 -----|---------|---------- Each student has a mentor who is also a student. There

问题 I have a UserAssignmentRole class like this : @Data @Entity public class UserAssignmentRole { ... @Enumerated(EnumType.STRING) public Role role; } And the Role is enum, it looks like this: public enum Role{ admin, member, pending } Now when in my repository I try to query to select all with role of admin, it gives me error: @Query("select uar from UserAssignmentRole uar where uar.role=Role.admin") public List<UserAssignmentRole> listAdmin(Long userID, Long assignmentID); How this can be

问题 According to EclipseLink documentation it supports subqueries in the select clause (even if JPA doesn't require it). When I try to use this feature in JPA Criteria API: myCriteriaQuery .multiselect(Arrays.asList(mySubquery, ...)) .where(...) there is an error: java.lang.ClassCastException: org.eclipse.persistence.internal.jpa.querydef.SubQueryImpl cannot be cast to org.eclipse.persistence.internal.jpa.querydef.SelectionImpl at org.eclipse.persistence.internal.jpa.querydef.CriteriaQueryImpl

问题 Hi I have set up a Spring MVC (4)+Postgresql+JPA app and I encountered the following situation: I want to set up custom queries for my "User" repository so added these lines to the existing (empty) UserRepository: public interface AccountRepository extends JpaRepository<User,Long> { @Query("select u from User u where u.Email = ?1") User findByEmail(String emailAddress); } With the empty Repository, everything is OK with the server, with the verison above I got the following exception on

问题 Given the following code public class Course { @Id @GeneratedValue private Long id; private String name; @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true) private List<Review> reviews = new ArrayList<>(); } public class Review { @Id @GeneratedValue private Long id; @Column(nullable = false) private String rating; private String description; } Saved course with 2 reviews. If I try to remove one review from course. course.getReviews().remove(0); Hibernate fires following queries.

问题 I have a OneToMany association with two entities that I have set up using Hibernate annotations. The Child entity of this association has a composite primary key that consists of the foreign key parent column and another identifier childName . This seems to cause a "Referential integrity constraint violation" when I attempt to cascade a commit to the parent by saving the child entity. I have created a simple working example of the issue that abstracts away from the actual scenario that I am

问题 Normally Id column is as follows and it works perfectly fine and generated sequence values @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "idGenerator") @SequenceGenerator(name = "idGenerator", sequenceName = "HIBERNATE_SEQUENCE", allocationSize = 50) @Column(name = "ID") public Long getId() { return mId; } Now what I want is if in program I set xyz.setId(200) it should save Id as 200 instead of one generated by sequence.Now how can I acheive this? I also want to use both

问题 We are developing an application in spring boot, where we will be creating and publishing dynamic forms into our application at runtime to post the form-data into the db (MySql) in JSON format. We want to create a generic api to handle CRUD operations for all dynamic forms. We know about the php code-igniter framework query builder, which is capable to build and execute the queries. https://www.codeigniter.com/userguide3/database/query_builder.html#inserting-data For example : $query = $this-

问题 I have an Entity like below: @Entity public class Order { @Id private String orderId; @Temporal(TemporalType.TIMESTAMP) @Column(name = "created_at", nullable = false) private Date created; @Temporal(TemporalType.TIMESTAMP) @Column(name = "updated_at", nullable = false) private Date updated; @PrePersist protected void onCreate() { this.created = new Date(); this.updated = this.created; } @PreUpdate protected void onUpdate() { this.updated = new Date(); } } I have to find all the orders that