eclipselink

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed last year . I was wondering if anyone has experience with the JPA2.0 implementation of any of those frameworks? Especially together with Spring3.x which comes with EclipseLink support. Do you use any of those frameworks and JPA2.0 for production? Any severe issues? 回答1: IMHO It is always

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed last year . I was wondering if anyone has experience with the JPA2.0 implementation of any of those frameworks? Especially together with Spring3.x which comes with EclipseLink support. Do you use any of those frameworks and JPA2.0 for production? Any severe issues? 回答1: IMHO It is always

问题 Follow my code: Company cc = em.find(Company.class, clientUser.getCompany().getId()); System.out.println(cc.getCompany_code()); HashMap findProperties = new HashMap(); findProperties.put(QueryHints.CACHE_RETRIEVE_MODE, CacheRetrieveMode.BYPASS); Company oo = em.find(Company.class, clientUser.getCompany().getId(), findProperties); System.out.println(oo.getCompany_code()); Just like the example "Used as EntityManager properties". here But, there are nothing different between the two outputs.

问题 Address has many-to-one relationship with person like : Person : @Id @Column(name="personid") private Long personId; private String firstName; private String lastName; private String email; @OneToMany(cascade = CascadeType.ALL,mappedBy="person",targetEntity=Address.class,fetch=FetchType.LAZY) private List addressArray=new ArrayList<>(); public Person() { } and Address : @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name="personId") private Person person; I want to access person's firstname

问题 Given below a one-to-many relationship from Department to Employee . Department (parent) : @OneToMany(mappedBy = "department", fetch = FetchType.LAZY, cascade = CascadeType.ALL) private List<Employee> employeeList = new ArrayList<Employee>(0); Employee (child) : @JoinColumn(name = "department_id", referencedColumnName = "department_id") @ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH, CascadeType.DETACH}) private Department department;

问题 I have a descriptor class for a couple of domain classes. The descriptor class has a field 'type' which is an enum and indicates the type of the domain class. In some queries I want to return on or more descriptors and pass the type as constructor argument. So my idea was to pass it as a query parameter: String jpql = "SELECT NEW model.ModelDescriptor" + "(t.id, t.name, t.description, :modelType) ... "; TypedQuery<ModelDescriptor> query = em.createQuery(jpql, ModelDescriptor.class); query

问题 I have a table named group_table in MySQL with only two columns user_group_id and group_id (both of them are of type VARCHAR ). Both of these columns together form a composite primary key. I need to execute a statement using a sub-select IN() to select rows based on a list of values passed to the query. @Override @SuppressWarnings("unchecked") public List<GroupTable> getList(List<GroupTable> list) { CriteriaBuilder criteriaBuilder=entityManager.getCriteriaBuilder(); CriteriaQuery<GroupTable>

问题 There is the possibility to disable the @OneToMany relationship join table with the @JoinColumn annotation. The default is a join table. What are the advantages and disadvantages for a production system for example? When should I use a join table and when not? Thank you. 回答1: By default @OneToMany will create a join table only if you'll use unidirectional relationship . In other words, if you have Employee and Project entities and the Employee entity is defined as follows (assume there is no

问题 I'd like to find out my data source name in the code. Is there a way of doing that? I am using eclipselink. thanks To be more specific, my aim is to get an jdbc connection object. I know i can do that thru: datasource = (DataSource) (new InitialContext()).lookup("my_data_source_name") connection = dataSource.getConnection(); But I don't want to hard code the data source name in my code. I also tried java.sql.Connection connection = em.unwrap(java.sql.Connection.class); and it always return

问题 Is is possible (without writing custom SQL) to have Eclipselink trust me as to whether to perform an update or insert on a merge, rather than perform a select, then an update or insert? If so, how? In my mind I'd like to use a transient flag and a custom if statement to determine whether the item is already in the database or not, and instruct eclipselink to perform the query required. I understand Hibernate provides this as update() and save() A few notable points: I have a large amount of