objectbox - 在对象框实体中仅插入唯一值

Question

是否有类似的东西：@Insert(onConflict = OnConflictStrategy.REPLACE) 可以在 Objectbox 中执行的 Room 数据库中找到。如果没有，您如何避免在对象框实体中保存重复条目？谢谢。

Answer 1

在对象框 DataModel 类中，对项目进行注释

@unique 公共字符串用户 ID；

---

private Box<User> userBox;
userBox = ObjectBox.get().boxFor(User.class);

//your inserted object 

if (!userBox.getAll().contains(insertedObject)){
                        leadBoxForLeadOpions.put(l);
                    }

Answer 2

替换对象应该足够简单，@id(assignable=true)只需将注释设置为想要的 id 字段。我已经通过以下方式在我的 android 应用程序中对其进行了测试：

@Test
fun testAssignableIdsGetReplaced() {
    val myUser1 = User()
    myUser1.id = 1
    myUser1.nickname = "Original"
    var currentList = boxStore!!.boxFor(User::class.java).all
    assert(currentList.size == 0)
    boxStore!!.boxFor(User::class.java).put(myUser1)
    currentList = boxStore!!.boxFor(User::class.java).all
    assert(currentList.size == 1)
    assert(currentList.get(0).id == 1L)
    val newUser1 = User()
    newUser1.id = 1
    newUser1.nickname = "New"
    boxStore!!.boxFor(User::class.java).put(newUser1)
    currentList = boxStore!!.boxFor(User::class.java).all
    assert(currentList.size == 1)
    assert(currentList.get(0).id == 1L)
    assert(currentList.get(0).nickname == newUser1.nickname)
}

@Entity
class User() {
  @Id(assignable = true) var id: Long = 0
  lateinitvar nickname: String
}

但请记住，使用 ids 可分配注释可能会产生副作用： https://docs.objectbox.io/relations#updating-relations
https://docs.objectbox.io/advanced/object-ids#self-assigned-object-身份证