我在关系中有两个实体
tag <-m:n-> software
并且我想在删除特定标签后删除所有不再链接到标签的软件。我为此编写了 HQL 查询..
我使用游戏框架
我被覆盖的 Tag.delete()
@Override
public Tag delete() {
Tag t = null;
// t = super.delete(); // commented for now
// it should delete ONLY that softwares which are not linked with tags (tags is empty)
Query q = Tag.em().createQuery("delete from Software s where s.tags is empty ");
q.executeUpdate();
return t;
}
我的测试：
@Test
public void testDelete() throws InterruptedException {
Tag tag1 = new Tag("tag1").save();
Tag tag2 = new Tag("tag2").save();
Author author1 = new Author("name", "email").save();
Software s1 = new Software("soft1", "description1", author1, tag1).save(); // this should be deleted when tag1 is deleting
Software s2 = new Software("soft2", "description2", author1, tag1, tag2).save(); // this should be deleted, because it links to tag2
// checks, just in case:
Software ss = Software.findById(s1.id);
assertTrue(ss.isPersistent());
assertTrue(!ss.tags.isEmpty());
assertEquals(1, ss.tags.size());
tag1.delete();
// try to find the software
assertEquals(1, Software.findAll().size()); // here it faults, it deletes all!!!
}
现在我的问题是它会删除所有软件，即使它们有标签链接。
但我得到了由 HQL 形成的 SQL，它就像：
delete from Software where not (exists (select tag.id from Tag_Software ts, Tag tag where Software.id=ts.softwares_id and ts.tags_id=tag.id))
它是很好的 SQL（我检查了它），但是为什么在我的上下文中这一切都不能作为 HQL 工作......？
我的测试说：
失败，预期：<1> 但结果：<0>
两个类的代码是：
public class Tag extends Model {
@Column(nullable = false, unique = true)
public String title;
public Tag(String title) {
this.title = title;
}
@ManyToMany
public List<Software> softwares = new LinkedList<Software>();
……
@Entity
public class Software extends Model {
public String title;
public String description;
@ManyToOne(optional = false)
public Author author;
@ManyToMany(mappedBy = "softwares")
public List<Tag> tags = new LinkedList<Tag>();
...