Question

我有一个与许多酒吧有关系的foo。

当我删除系统中的bar时，我想将它们保存在数据库中，这是出于某种疯狂的商业原因所以我只是将删除的字段设置为true。

我可以在我的hibernate映射中指定我只希望我的集合保存该字段为false的元素吗？

Answer 1

您还可以使用SQL语句来保留内容，使用 where 属性：hibernate映射文件的示例位用于设置关系：

<set name="specialConditions" cascade="none" order-by="sortOrder, Text1" 
  where="Discriminator in ( 'SPECIAL-CURF-AGREEMENT' ) and active = 'Y'" 
  sort="unsorted" inverse="false" mutable="true" optimistic-lock="true" 
  embed-xml="true">    
  <key column="parentID" not-null="false" on-delete="noaction" /> 
  <one-to-many class="au.gov.abs.maserati.domain.entity.Condition" not-found="exception" embed-xml="true" /> 
</set>

Answer 2

Hibernate提供filters来完成此任务。

示例bean：

public class Foo {
    private Long id;
    private String text;
    private Set<Bar> bars = new HashSet<Bar>();    
    // constructors, getters, setters
}

public class Bar {
    private Long id;
    private boolean deleted;
    private String text;
    // constructors, getters, setters
}

示例映射 NB：filter元素

<hibernate-mapping package="org.nkl.hib">
  <class name="Foo">
    <id name="id" column="FOO_ID">
      <generator class="sequence" />
    </id>
    <property name="text" />
    <set name="bars" cascade="all" fetch="join">
      <key column="FOO_ID" />
      <one-to-many class="Bar" />
      <filter name="deleted" condition=":deleted = deleted" />
    </set>
  </class>
  <filter-def name="deleted">
    <filter-param name="deleted" type="boolean" />
  </filter-def>
</hibernate-mapping>

<hibernate-mapping package="org.nkl.hib">
  <class name="Bar">
    <id name="id" column="BAR_ID">
      <generator class="sequence" />
    </id>
    <property name="text" />
    <property name="deleted" />
  </class>
</hibernate-mapping>

单元测试示例：

public class FooBarTest {

    private static SessionFactory sessionFactory;

    @AfterClass
    public static void closeSessionFactory() {
        sessionFactory.close();
    }

    @BeforeClass
    public static void setupSessionFactory() {
        Configuration configuration = new Configuration();
        configuration.configure();
        sessionFactory = configuration.buildSessionFactory();
    }

    @Test
    public void testBarFilter() {
        doInTransaction(new Command() {
            public void execute(Session session) {
                Foo foo = new Foo("foo");
                foo.addBar(new Bar("bar1"));
                foo.addBar(new Bar("bar2"));
                foo.addBar(new Bar("bar3"));
                session.save(foo);
            }
        });

        doInTransaction(new Command() {
            public void execute(Session session) {
                Bar bar = (Bar) session.createQuery(
                        "from Bar b where b.text = 'bar2'").
                        uniqueResult();
                bar.setDeleted(true);
                session.update(bar);
            }
        });

        doInTransaction(new Command() {
            public void execute(Session session) {
                session.enableFilter("deleted").
                        setParameter("deleted", Boolean.FALSE);
                Foo foo = (Foo) session.createQuery("from Foo").
                        uniqueResult();
                assertEquals(2, foo.getBars().size());
            }
        });
    }

    private void doInTransaction(Command command) {
        Session session = sessionFactory.openSession();
        Transaction tx = session.beginTransaction();
        command.execute(session);
        tx.commit();
        session.close();
    }
}

interface Command {
    public void execute(Session session);
}

我可以用过滤器指定一个休眠关系吗？

2 个答案: