如何设计一个简单的 Firebase 数据库来存储数组? [英] How do I design a simple Firebase Database that stores arrays?

问题描述

我正在 Swift 中使用 Xcode 8.2.1 编写 IOS 应用程序.目前，我为一个视图控制器设置了数据库，该控制器实现了 GeoFire 并成功地向数据库添加了位置.在单独的视图控制器上，我想添加对同一数据库的引用并将子项添加到此引用.

I am in the midst of coding an IOS application using Xcode 8.2.1 in Swift. Currently, I have the database set up for one view controller that implements GeoFire and successfully adds locations to the database. On a separate view controller, I want to add a reference to the same database and add children to this reference.

这个单独的引用我想存储可以通过数组名访问的不同数组.我希望能够在数据库中添加和删除保存的数组.此外，我希望能够添加和删除保存在每个单独数组中的字符串.

This separate reference I want to store different arrays that can be accessed by the array name. I want to be able to add and remove the saved arrays in the database. In addition, I want to be able to add and remove the strings that are held in each individual array.

我试过的代码是:

    let ref = FIRDatabase.database().reference()

    let childRef = FIRDatabase.database().reference(withPath: "arrays")

    let itemsRef = ref.child("arrays")

    let milkRef = itemsRef.child("array1")

但是当我运行此代码时，数据库不会更新以显示任何新子项.有可能完成我的任务吗?如果是这样，我做错了什么?

But when I run this code, the database does not update to show any new children. Is it possible to accomplish my task? If so, what am I doing wrong?

如果我的问题有任何不清楚，请告诉我，我愿意详细说明.在此先感谢您的帮助！

If my question is unclear in any way please let me know and I will be willing to elaborate. Thank you in advance for any help!

推荐答案

阅读此内容:数组是邪恶的

通常最好避免使用它们，因为通常有更好的方法来组织您的数据.

In general it's best of avoid them as there are usually better ways to organize your data.

这里有一些信息:

这将创建一个名为 child_node 的节点并为其分配一个 some_value 的值

This creates a node called child_node and assigns it a value of some_value

let ref = FIRDatabase.database().reference()
let childRef = ref.child("child_node")
childRef.setValue("some_value")

结果

root
  child_node: some_value

如果再次运行代码，它将覆盖现有节点.

If you run the code again, it will overwrite the existing node.

一般来说，最好将节点名称与其包含的数据分离，以便稍微扩展

In general it's best to disassociate nodes names from the data they contain so expanding a bit

let ref = FIRDatabase.database().reference()
let childRef = ref.childByAutoId()
childRef.setValue("some_value")

结果

root
   -Y8hjj9a99js9jd: some_value
   -Yi00ksomosooss: some_value //the second time it's run

然后走得更远

let ref = FIRDatabase.database().reference()
let childRef = ref.childByAutoId()
let someData = ["site": "Olympus Mons", "location": "Mars"]
childRef.setValue(someData)

结果

root
   -Y88ujs9mskkms:
         site: "Olympus Mons"
         location: "Mars"

然后你问自己自己，这与数组有什么关系"?

So you then ask yourself 'self, what does this have to do with arrays'?

这是存储额外"数据的更好方法.例如，您可以在他们的节点中存储用户位置

It's a better way to store 'extra' data. So for example you could store a users location within their node

root
  users
     -Yi8joiomso (uid)
         g: xxxx
         l:
           0: xxx
           1: xxx

或保留对它们在另一个节点中位置的引用

or keep a reference to where they are in another node

root
  users
     -Yi8joiomso (uid)
       location: -Yiuhj89ejee
  location
     -Yiuhj89ejee
         g: xxxx
         l:
           0: xxx
           1: xxx

或将用户保留在位置节点内

or keep the users within the location node

root
  location
    userID
       g: xxxx
       l:
          0: xxxx
          1: xxxx

非数组结构为查询、检索数据和组织数据提供了更大的灵活性.

Non-array structures give far more flexibility for queries, retrieving data and organizing data.

这篇关于如何设计一个简单的 Firebase 数据库来存储数组?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！