使用 Swift Realm,我想从 parent 的角度获得 child 的所有者。
简单来说,实体关系可以描述为:
Parent -< Child <- Player
我想使用给定的 Parent 获取玩家(所有者)列表。
当我尝试查询时,我认为我的查询是错误的;
// Cut-down summary of Realm objects and relationships
public class Parent: Object {
var children = List<Child>()
}
public class Child: Object {
private let parents = LinkingObjects(fromType: Parent.self, property: "children")
private let owners = LinkingObjects(fromType: Player.self, property: "children")
var parent:Parent? {
return self.parents.first
}
var owner: Player? {
return self.owners.first
}
}
public class Player : Object {
public let children = List<Child>()
}
let realm = try! Realm()
self.createPlayers(amount: 5)
let playerList = realm.objects(EYPlayer.self)
XCTAssert(playerList.count == 5)
// In my tests:
let firstParent = realm.objects(Parent.self).first
let firstChild = firstParent?.children.first
let firstPlayer = realm.objects(Player.self).first
// Assign the first player with the first child
try! realm.write {
firstPlayer?.children.append(firstChild!)
}
// give me a list of owners for a given parent
let owners = realm.objects(Parent.self).filter("ANY children.owners.@count > 0")
print (owners)
// Test fails; it says there are 0 results
XCTAssert(owners.count == 1, "Expected: 1, Found: \(owners.count)")
这个测试失败了:
XCTAssert(owners.count == 1, "Expected: 1, Found: \(owners.count)")
我希望有 1 个所有者。
但相反,我有 0 个所有者。
我做错了什么?
如何使用 NSPredicates 和 Realm 获取给定子项的所有者列表?
非常感谢
编辑:发现我没有添加任何玩家;添加播放器的摘要版本如上所示
最佳答案
我现在已经解决了这个问题。
- 没有玩家数据可以追加 child ;我已经在我的 xctests 中解决了这个问题
执行此操作并对我的测试进行一些调整后,查询似乎有效并在我的记录器输出中进行了验证。
let firstParent = realm.objects(Parent.self).first let firstPlayer = realm.objects(Player.self).first let firstChild = firstParent?.children.first XCTAssert(firstChild?.parent == firstParent) try! realm.write { firstPlayer!.children.append(firstChild!) } let listOfChildren = realm.objects(Parent.self).filter("ANY children.owners.@count > 0") XCTAssert(listOfChildren.count == 1) XCTAssert(firstPlayer?.children.count == 1) for child in listOfChildren { for (index, eng) in child.children.enumerated() { if (index == 0) { XCTAssert(eng.owner != nil) } XCTAssert(child.parent == loco) } }
测试通过,并且通过一些控制台日志我能够验证我的期望。
问题已解决。
关闭。
关于swift - Realm - 如何获取父子关系中实体所有者的列表?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41789832/