hibernate-mapping

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 i am trying to generate Entity Classes from MySQL database using Hibernate Tools (Annotations) in Eclipse. However, I am having trouble in generating one-to-one relationship code. My MySQL table is currently ensuring this relationship yet Hibernate tools does not detect it... "A User is Associated with Exactly One Employee" Here is the code for my tables.. Users first CREATE TABLE `user` ( `user_id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(20) NOT NULL, `password` varchar(45) NOT

问题 Our problem is that we can't get data (which includes empty strings with length 0) from a legacy database due to a StringIndexOutOfBoundsExceptiion originating from Hibernate's CharacterTypeDescriptor . We would like to change Hibernate's behavior to properly resolve empty strings. Example data: 1, 'Berlin', 17277, '', 'aUser' 2, 'London', 17277, '', 'anotherUser' We use hibernate with javax.persistence.Query . String sql = "SELECT * FROM table"; Query query = entityManager.createNativeQuery

问题 Our problem is that we can't get data (which includes empty strings with length 0) from a legacy database due to a StringIndexOutOfBoundsExceptiion originating from Hibernate's CharacterTypeDescriptor . We would like to change Hibernate's behavior to properly resolve empty strings. Example data: 1, 'Berlin', 17277, '', 'aUser' 2, 'London', 17277, '', 'anotherUser' We use hibernate with javax.persistence.Query . String sql = "SELECT * FROM table"; Query query = entityManager.createNativeQuery

问题 Our problem is that we can't get data (which includes empty strings with length 0) from a legacy database due to a StringIndexOutOfBoundsExceptiion originating from Hibernate's CharacterTypeDescriptor . We would like to change Hibernate's behavior to properly resolve empty strings. Example data: 1, 'Berlin', 17277, '', 'aUser' 2, 'London', 17277, '', 'anotherUser' We use hibernate with javax.persistence.Query . String sql = "SELECT * FROM table"; Query query = entityManager.createNativeQuery

问题 I'm using Hibernate 4.3.8.Final and Oracle 11g database. I defined a very simple bidirectional relationship between two entities, named Parent and Child, as follows (getters and setters are omitted): @Entity public class Parent { @Id private Long id; @OneToOne(mappedBy="parent",fetch=FetchType.LAZY) private Child child; } @Entity public class Child { @Id private Long id; @OneToOne(fetch=FetchType.EAGER) @JoinColumn(name="PARENT_ID") private Parent parent; } The SQL code which generates the

问题 Hi below is my entities with manytoone association between them student.java @Entity @Table(name = "student") public class student{ @Id @Column(name = "UserID") private String userid; @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY) @JoinColumns({ @JoinColumn(name = "userrole", referencedColumnName = "VALUE"), @JoinColumn(name = "userrole", referencedColumnName = "DESCRIPTION") }) private studentdetails userrole; //setters and getters //constructor } studentdetails.java @Data

问题 Hi below is my entities with manytoone association between them student.java @Entity @Table(name = "student") public class student{ @Id @Column(name = "UserID") private String userid; @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY) @JoinColumns({ @JoinColumn(name = "userrole", referencedColumnName = "VALUE"), @JoinColumn(name = "userrole", referencedColumnName = "DESCRIPTION") }) private studentdetails userrole; //setters and getters //constructor } studentdetails.java @Data

问题 Hi below is my entities with manytoone association between them student.java @Entity @Table(name = "student") public class student{ @Id @Column(name = "UserID") private String userid; @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY) @JoinColumns({ @JoinColumn(name = "userrole", referencedColumnName = "VALUE"), @JoinColumn(name = "userrole", referencedColumnName = "DESCRIPTION") }) private studentdetails userrole; //setters and getters //constructor } studentdetails.java @Data

问题 Why does JPA OneToOne (or even OneToMany for that matter) have its orphanRemoval default to false . I mean, wouldn't it be better to force the remove operation to entities that have been removed from the relationship and to cascade the remove operation to those entities by default & have the user make the choice to not do it explicitly? Would the current behavior of the default being false not result in orphan entries (that might potentially become zombie records) that might lead to bloat of