Swift Group Realm查询结果 [英] Swift group Realm query results

问题描述

我在Swift应用程序中关注了Realm对象(为简洁起见删除了init和其他非必要属性)

I've following Realm objects (init and other non-essential properties removed for brevity) in my Swift app

@objcMembers
class Person: Object {
    dynamic var id: String = ""
    dynamic var name: String = ""

    override static func primaryKey() -> String? {
        return "id"
    }
}

@objcMembers
class Project: Object {
    dynamic var projectId: Int = 0
    dynamic var manager: Person?
    var tasks = List<Task>()
    dynamic var lastTask: Task?

    override static func primaryKey() -> String? {
        return "projectId"
    }
}

@objcMembers
class Task : Object {
    dynamic var project = LinkingObjects(fromType: Project.self, property: "tasks")
    dynamic var taskId: String = ""
    dynamic var description: String = ""
    dynamic var createDate: Date = Date()

    override static func primaryKey() -> String? {
        return "taskId"
    }
}

所以如果有2个项目成员

So if there are 2 project members

人员(id:1，名称:"Foo")

Person(id: 1, name: "Foo")

人员(id:2，名称:"Bar")

Person(id: 2, name: "Bar")

和多个项目，

Project(projectId:100，manager:，消息:[a1，a2，a3]， lastMessage:)

Project(projectId: 100, manager: , messages: [a1, a2, a3], lastMessage: )

a1 =任务(项目:<#100>，任务ID:"a1"，说明:任务1关于 项目100"，createDate:Date())

a1 = Task(project: <#100>, taskId: "a1", description: "Task 1 about project 100", createDate: Date() )

a2 =任务(项目:<#100>，任务ID:"a2"，说明:任务2关于 项目100"，createDate:Date())

a2 = Task(project: <#100>, taskId: "a2", description: "Task 2 about project 100", createDate: Date() )

a3 =任务(项目:<#100>，任务ID:"a3"，说明:任务3关于 项目100"，createDate:Date())

a3 = Task(project: <#100>, taskId: "a3", description: "Task 3 about project 100", createDate: Date() )

Project(projectId:101，manager:，消息:[a1，a2，a3]， lastMessage:)

Project(projectId: 101, manager: , messages: [a1, a2, a3], lastMessage: )

b1 =任务(项目:<#101>，任务ID:"b1"，说明:任务1关于 项目101"，createDate:Date())

b1 = Task(project: <#101>, taskId: "b1", description: "Task 1 about project 101", createDate: Date() )

b2 =任务(项目:<#101>，任务ID:"b2"，说明:任务2关于 项目101"，createDate:Date())

b2 = Task(project: <#101>, taskId: "b2", description: "Task 2 about project 101", createDate: Date() )

b3 =任务(项目:<#101>，任务ID:"b3"，说明:任务3关于 项目101"，createDate:Date())

b3 = Task(project: <#101>, taskId: "b3", description: "Task 3 about project 101", createDate: Date() )

b4 =任务(项目:<#101>，任务ID:"b3"，说明:任务3关于 项目101"，createDate:Date())

b4 = Task(project: <#101>, taskId: "b3", description: "Task 3 about project 101", createDate: Date() )

Project(projectId:102，manager:，消息:[a1，a2，a3]， lastMessage:)

Project(projectId: 102, manager: , messages: [a1, a2, a3], lastMessage: )

c1 =任务(项目:<#102>，任务ID:"c1"，说明:任务1关于 项目102"，createDate:Date())

c1 = Task(project: <#102>, taskId: "c1", description: "Task 1 about project 102", createDate: Date() )

Project(projectId:103，manager:，消息:[a1，a2，a3]， lastMessage:)

Project(projectId: 103, manager: , messages: [a1, a2, a3], lastMessage: )

d1 =任务(项目:<#103>，taskId:"d1"，描述:任务1关于 项目103"，createDate:Date())

d1 = Task(project: <#103>, taskId: "d1", description: "Task 1 about project 103", createDate: Date() )

d2 =任务(项目:<#103>，任务ID:"d2"，说明:任务2关于 项目103"，createDate:Date())

d2 = Task(project: <#103>, taskId: "d2", description: "Task 2 about project 103", createDate: Date() )

d3 =任务(项目:<#103>，任务ID:"d3"，说明:任务3关于 项目103"，createDate:Date())

d3 = Task(project: <#103>, taskId: "d3", description: "Task 3 about project 103", createDate: Date() )

在我的ProjectsViewController中

In my ProjectsViewController

我可以得到我的Realm结果

I can get my Realm results as

func getProjects() -> Results<Project> {
    let results: Results<Conversation> = database
        .objects(Conversation.self)
        .sorted(byKeyPath: "lastTask.createDate", ascending: false)

    return results
}

[附注-如果有更好的方法根据任务列表的最后一项对结果进行排序，请告诉我.这将使lastTask var的使用变得多余.]

在我的表格视图中显示为

which will display in my table view as

===================
Projects
-------------------
Foo 
Project 100
Task a3 
-------------------
Bar 
Project 101
Task b4
-------------------
Foo
Project 102
Task c1 
-------------------
Bar
Project 103
Task d3 
-------------------

问题:如何在Realm查询中对结果进行分组，以便获得结果数组的字典，例如

Question: How do I group the results in Realm query so I get a dictionary of grouped Array of results, such as

Foo-> [Project 100，任务数组]，[Project 102，任务数组]

Foo -> [Project 100, Array of Tasks], [Project 102, Array of Tasks]

Bar-> [Project 101，任务数组]，[Project 103，任务数组]

Bar -> [Project 101, Array of Tasks], [Project 103, Array of Tasks]

，并通过NotificationToken跟踪所有插入/更新.另外，我想按表格视图中的各个部分对它们进行布局.

and they're tracked via NotificationToken for all inserts / updates. Also I want to dislay them grouped by sections in the table view.

===================
Projects (Grouped)
-------------------
Foo (Section Header)
-------------------
Project 100
Task a3 
-------------------
Project 102
Task c1 
-------------------


-------------------
Bar (Section Header)
-------------------
Project 101
Task b4
-------------------
Project 103
Task d3 
-------------------

推荐答案

我将根据您的询问 回答.

I'll answer based on what I think you're asking.

如果我理解正确，您想找到一个以Person作为键的字典，值是一个以Project ID(或Project)作为键和任务数组的值的字典.即

If I understand correctly, you want to find a dictionary with the Person as the key, the values being a dictionary with Project ID (or Project) as the key and values of an array of tasks. i.e.

let result : [Person:[Project:[Task]]] = .....

如果这是不正确的，您可以在这里接受这些想法，然后将它们按摩成您的理想状态.

If this isn't correct, you can probably take the ideas here and massage them into your ideal.

当您想按Person键输入时，我将向Person类添加一个反向查找属性-这可能是您缺少的主要内容.请查看手册的这一部分以获取指导:( https://realm.io/docs/swift/latest/#inverse-relationships )，然后将此属性添加到Person:

As you want to key by Person, I'd add a reverse lookup property to the Person class - and this is probably the main thing you're missing. Look at this section of the manual for guidance: (https://realm.io/docs/swift/latest/#inverse-relationships), and then add this property to Person:

let projects = LinkingObjects(fromType: Project.self, property: "manager")

然后我将向Person添加一个计算属性，以检索项目和任务.这创建了一个数组，因为在问题中要求这样做.

I would then add a computed property to Person to retrieve the projects and tasks. This creates an array since that was asked for in the question.

var projectsAndTasks : [Project:[Task]]
{
  var result : [Project:[Task]] = [:]
  for project in projects
  {
    result[project] = project.tasks.map { $0 }
  }

  return result
}

如果您希望对任务进行排序，请在Projects中添加一个名为sortedTasks的计算属性，为您执行此操作.

If you want the tasks to be sorted, then add a computed property to Projects called sortedTasks that does that for you.

完成后，您可以在某个位置添加一个函数(Person可以是全局的也可以是静态的)，以将Person的所有对象的结果添加到单个字典中.例如. :

Once that's done, you can add a function somewhere (either global or static to Person) to add the results for all objects of Person into a single dictionary. E.g. :

extension Realm
{
  var allPersonsAndProjects : [Person:[Project:[Task]]]
  {
    var result : [Person:[Project:[Task]]] = []
    let persons = objects(Person.self)
    for person in persons
    {
      result[person] = person.projectsAndTasks
    }

    return result
  }
}

原谅任何编译错误.

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