Question

考虑：

Rails.application.configure do
  config.cache_classes = false
  config.eager_load = false
  config.consider_all_requests_local = true
  if Rails.root.join('tmp/caching-dev.txt').exist?
  config.action_controller.perform_caching = true
  config.cache_store = :memory_store
  config.public_file_server.headers = {
  'Cache-Control' => 'public, max-age=172800'
    }
  else
    config.action_controller.perform_caching = false
config.cache_store = :null_store
  end
  config.active_support.deprecation = :log
  config.active_record.migration_error = :page_load
  config.assets.debug = true
  config.assets.quiet = true
  config.file_watcher = ActiveSupport::EventedFileUpdateChecker
end

和

@Entity
public class Foo {
    @EmbeddedId
    private FooPK pk;

    public FooPK getPk() { return pk; }
    public void setPk(FooPK pk) { this.pk = pk; }
}

我有一个@Embeddable public class FooPK { @Column(name="ID_A") private Long idA; @Column(name="ID_B") private Long idB; public Long getIdA() { return idA; } public void setIdA(Long idA) { this.idA = idA; } public Long getIdB() { return idB; } public void setIdB(Long idB) { this.idB = idB; } }我想在HQL中用作过滤器：

List<FooPK>

这不起作用，因为-- Just an example of what I'm trying to do. SELECT foo FROM Foo foo WHERE foo.pk IN (:pkList)不是单个值。我只是想列出我拥有pks的所有实体。

我可以打破列表并执行以下操作：

pk

但我相信你可以看到这是多么丑陋和不可扩展。

我正在使用Java 6 / JPA 1 / Hibernate 3

对于它的价值，我正在使用Oracle，我期望生成的SQL类似于：

-- Ugly
SELECT foo FROM Foo foo
WHERE (
       (foo.pk.idA = :idA1 AND foo.pk.idB = :idB1)
    OR (foo.pk.idA = :idA2 AND foo.pk.idB = :idB2)
    OR (foo.pk.idA = :idA3 AND foo.pk.idB = :idB3)
    -- ...
)

Answer 1

您可以使用Criteria API替换hql。

// your list of FooPks
List<FooPk> pkList = ....

//Create a criteria over an entity
Criteria  criteria = session.createCriteria(Foo.class);
// add a restriction
criteria.add(Restrictions.in("pk", pkList));
// Execute query and get result.
List<Foo> foos = criteria.list();

Answer 2

以下适用于MySQL：

为javax.persistence.NamedQuery

创建@Entity

@NamedQuery(name = "select", query = "SELECT foo FROM Foo foo WHERE foo.pk IN :pks")

通过

选择

final TypedQuery<Foo> typedQuery = this.entityManager.createNamedQuery("select", Foo.class);
final FooPK fooPk = new FooPK(...); // Create example FooPK
typedQuery.setParameter("pks", Arrays.asList(fooPk, fooPk));

return typedQuery.getResultList();

生成的SQL：

select ... from ... where foo0_.idA=? and foo0_.idB=? or foo0_.idA=? and foo0_.idB=?

（请注意每个idA和idB）

如何使用HQL通过所述PK列表过滤具有复合PK的实体？

2 个答案: