假設(shè)檢驗(yàn)方差未知

by Rick Mak

麥瑞克(Rick Mak)

設(shè)計(jì)云數(shù)據(jù)庫時(shí)如何處理未知數(shù)并做出假設(shè) (How to handle unknowns and make assumptions when designing a cloud database)

場景：鞋盒還是社交應(yīng)用？ (Scenario: Shoebox or social app?)

Say you’re a developer who wants to build a note taking app. Let’s look at one feature detail with huge implications on your back-end. To write a note, your app will need to be able to save the data.

假設(shè)您是一名開發(fā)人員，想開發(fā)一個(gè)筆記應(yīng)用程序。 讓我們來看一個(gè)對(duì)后端有重大影響的功能細(xì)節(jié)。 要寫筆記，您的應(yīng)用將需要能夠保存數(shù)據(jù)。

Saving a record to a database is straight forward. The key questions are:

將記錄保存到數(shù)據(jù)庫很簡單。 關(guān)鍵問題是：

• Who will need to access that record?
  誰需要訪問該記錄？
• Will it only be your user, or will your user share it with others?
  它只會(huì)是您的用戶，還是會(huì)與他人共享？
• Will your product be shoe-box app or a social app?
  您的產(chǎn)品是鞋盒應(yīng)用還是社交應(yīng)用？

If you intend for the notes to be private to the author, you may conclude that you are making a shoe-box app. This means all data goes to a private DB (database).

如果您打算使注釋對(duì)作者不公開，則可以得出結(jié)論，您正在制作鞋盒應(yīng)用程序。 這意味著所有數(shù)據(jù)都將進(jìn)入私有DB(數(shù)據(jù)庫)。

If you intend for your app to share notes with others, you may conclude it should be a public DB.

如果您打算讓您的應(yīng)用與他人共享筆記，則可以得出結(jié)論，它應(yīng)該是公共數(shù)據(jù)庫。

But will you know which it is before you start?

但是在開始之前您會(huì)知道是哪個(gè)嗎？

And what will you do if you need to change your product as you go? Public DB and private DB isn’t the first thing most developers think about when they’re building an app. We encountered these question when we were building our back-end product for our developers, Skygear.

如果您需要隨時(shí)隨地更改產(chǎn)品，該怎么辦？ 大多數(shù)開發(fā)人員在構(gòu)建應(yīng)用程序時(shí)都不會(huì)想到公共數(shù)據(jù)庫和私有數(shù)據(jù)庫。 在為開發(fā)人員Skygear構(gòu)建后端產(chǎn)品時(shí)，我們遇到了這些問題。

Because of our experience in building apps for clients, we assumed there was a right choice of database. And that our user would know how to choose.

基于我們?cè)跒榭蛻魳?gòu)建應(yīng)用程序方面的經(jīng)驗(yàn)，我們認(rèn)為數(shù)據(jù)庫是正確的選擇。 而且我們的用戶會(huì)知道如何選擇。

How do you build a back-end for developers who aren’t sure of their products needs yet? Or for those who want to keep their options open in the future?

您如何為尚不確定其產(chǎn)品需求的開發(fā)人員構(gòu)建后端？ 還是對(duì)于那些希望將來保留其選擇權(quán)的人？

As the tech lead in the project, I’d like to share with you our decision making process from 2 years ago. I hope it helps future development teams approach unknowns and assumptions.

作為該項(xiàng)目的技術(shù)負(fù)責(zé)人，我想與您分享我們2年前的決策過程。 我希望它可以幫助未來的開發(fā)團(tuán)隊(duì)?wèi)?yīng)對(duì)未知和假設(shè)。

為什么我們開始考慮私有數(shù)據(jù)庫與公共數(shù)據(jù)庫？ (Why did we start thinking about private vs public DBs?)

Many apps require a back-end to store and query user data. The back-end is a lot of hard work to build and, let’s face it — not so enjoyable to create. Skygear is our open-source serverless back-end. It helps address common development features for mobile and web apps.

許多應(yīng)用程序需要后端來存儲(chǔ)和查詢用戶數(shù)據(jù)。 后端是很多艱苦的工作，而讓我們面對(duì)現(xiàn)實(shí)-創(chuàng)建起來并不那么愉快。 Skygear是我們的開源無服務(wù)器后端。 它有助于解決移動(dòng)和Web應(yīng)用程序的常見開發(fā)功能。

The feature I’ll talk about is our Cloud DB, where you store and query user data. When we started to design Cloud DB, we asked ourselves how different apps store and query user data.

我將討論的功能是我們的Cloud DB，您可以在其中存儲(chǔ)和查詢用戶數(shù)據(jù)。 當(dāng)我們開始設(shè)計(jì)Cloud DB時(shí)，我們自問不同的應(yīng)用程序如何存儲(chǔ)和查詢用戶數(shù)據(jù)。

We looked at our company’s mobile apps portfolio for inspiration. Our company does everything from consumer apps to e-commerce apps. So we grouped them into “shoe-box” and “social” apps.

我們從公司的移動(dòng)應(yīng)用程序組合中尋找靈感。 從消費(fèi)類應(yīng)用程序到電子商務(wù)應(yīng)用程序，我們公司都應(yīng)運(yùn)而生。 因此，我們將它們分為“鞋盒”和“社交”應(yīng)用。

Shoe-box apps store personal data that the user wants to keep private. For example, our side project Spentable helps a user track of their daily spending. Data stored in the app is meant to be private, in a shoe-box.

鞋盒應(yīng)用程序存儲(chǔ)用戶想要保密的個(gè)人數(shù)據(jù)。 例如，我們的輔助項(xiàng)目Spentable可幫助用戶跟蹤他們的每日支出。 應(yīng)用程序中存儲(chǔ)的數(shù)據(jù)是在鞋盒中私有的。

But, there is stuff that we want to share publicly or with friends. That also means the user needs to be in control of who can read their data. These two kinds of apps present a challenge in how we designed Skygear’s Cloud DB. We wanted to make storing data in Cloud DB as easy as possible. For shoe-box apps, all the developers need is a database where each user can only see the data that they are putting in. Yet, in social apps, developers need features such as ACL (access control). How can we make things simple for developers of both kinds of apps?

但是，有些東西我們要公開或與朋友分享。 這也意味著用戶需要控制誰可以讀取其數(shù)據(jù)。 這兩種應(yīng)用程序?qū)ξ覀內(nèi)绾卧O(shè)計(jì)Skygear的Cloud DB提出了挑戰(zhàn)。 我們希望使數(shù)據(jù)存儲(chǔ)在Cloud DB中盡可能容易。 對(duì)于鞋盒應(yīng)用程序，開發(fā)人員所需的只是一個(gè)數(shù)據(jù)庫，每個(gè)用戶只能在其中查看他們所放入的數(shù)據(jù)。然而，在社交應(yīng)用程序中，開發(fā)人員需要ACL(訪問控制)等功能。 對(duì)于兩種應(yīng)用程序的開發(fā)人員，我們?nèi)绾问故虑樽兊煤唵?#xff1f;

吃我們的蛋糕也吃 (Having our cake and eating it too)

We decided to solve this problem by introducing the concept of multiple databases in the Cloud DB: private DB and public DB. Each user has a private DB to put data in, and that data is only available to the same user. The app also has one public DB that is shared among all users.

我們決定通過在Cloud DB中引入多個(gè)數(shù)據(jù)庫的概念來解決此問題：私有DB和公共DB。 每個(gè)用戶都有一個(gè)專用數(shù)據(jù)庫來放入數(shù)據(jù)，并且該數(shù)據(jù)僅可用于同一用戶。 該應(yīng)用程序還具有一個(gè)公共數(shù)據(jù)庫，該數(shù)據(jù)庫在所有用戶之間共享。

A shoe-box app developer is able to focus on saving and fetching the data without worrying about permissions because data in the private DB is always private.

鞋盒應(yīng)用程序開發(fā)人員能夠?qū)Ｗ⒂诒４婧瞳@取數(shù)據(jù)而無需擔(dān)心權(quán)限，因?yàn)樗接蠨B中的數(shù)據(jù)始終是私有的。

But, private DB does not work at all for social apps. Developers for social apps should put data in the public DB because data in social apps are meant to be shared.

但是，私有數(shù)據(jù)庫根本不適用于社交應(yīng)用程序。 社交應(yīng)用程序的開發(fā)人員應(yīng)將數(shù)據(jù)放入公共數(shù)據(jù)庫中，因?yàn)樯缃粦?yīng)用程序中的數(shù)據(jù)是要共享的。

Before we added support for ACL, this simple distinction for public and private data served us(and our users very well. Everything in private DB is truly private while everything is public DB is truly public.

在添加對(duì)ACL的支持之前，對(duì)公共數(shù)據(jù)和私有數(shù)據(jù)的這種簡單區(qū)分對(duì)我們(以及我們的用戶)都非常有用。私有DB中的所有內(nèi)容都是真正的私有，而公共DB中的所有內(nèi)容都是真正的公共。

“Everything is public” is not good enough. Most social apps have use cases that data is only shared among a group of friends.

“一切都是公共的”還不夠好。 大多數(shù)社交應(yīng)用都有用例，數(shù)據(jù)僅在一組朋友之間共享。

ACL is another difficult and interesting topic that should be it’s own article.

ACL是另一個(gè)困難而有趣的主題，應(yīng)該是它自己的文章。

我們無法同時(shí)利用這兩個(gè)數(shù)據(jù)庫的優(yōu)勢 (We couldn’t have the best of both databases)

Separating the DB into private and public ones was a good idea. We thought they supported the use case for majority of apps.

將數(shù)據(jù)庫分為私有和公共數(shù)據(jù)庫是一個(gè)好主意。 我們認(rèn)為他們支持大多數(shù)應(yīng)用程序的用例。

But early adopters found our private and public options confusing.

但是，早期采用者發(fā)現(xiàn)我們的私有和公共選擇令人困惑。

Our early users gave us invaluable feedback. We also paid attention to the support questions we received. This is what we learned from developer feedback when they used our Cloud DB:

我們的早期用戶給了我們寶貴的反饋。 我們還關(guān)注收到的支持問題。 這是我們從開發(fā)人員使用Cloud DB時(shí)的反饋中學(xué)到的：

It’s not obvious to developers what they’re building at first

對(duì)于開發(fā)人員而言，起初他們正在構(gòu)建的東西并不明顯

While it may be obvious which kind of app developer made by looking at the product retroactively, it is not obvious from the get-go. Forcing the developer to decide whether they are making a shoe-box or social app at the beginning is difficult, if not impossible.

回顧性地看待哪種應(yīng)用程序開發(fā)人員可能很明顯，但從一開始就并不明顯。 強(qiáng)迫開發(fā)人員決定一開始是制作鞋盒還是社交應(yīng)用是困難的，即使不是不可能的。

Developers just want to get started quickly

開發(fā)人員只想快速入門

We want the developers to learn the basics as quickly as possible. Having to learn one more concept to choose which DB to use before they can actually save and retrieve data is too much to ask for new users.

我們希望開發(fā)人員盡快學(xué)習(xí)基礎(chǔ)知識(shí)。 在實(shí)際保存和檢索數(shù)據(jù)之前，必須學(xué)習(xí)另一個(gè)概念來選擇要使用的數(shù)據(jù)庫，這對(duì)于尋求新用戶來說實(shí)在太多了。

The decision for public or private DB, once made, isn’t easy to reverse

一旦做出公共或私有數(shù)據(jù)庫的決定，就不容易撤銷

Suppose that a developer started with a shoe-box app idea and they put everything in the private DB. Later they may realize that they should make the app a social one instead. It is not easy to migrate data once they are put into a particular DB.

假設(shè)開發(fā)人員從一個(gè)鞋盒式應(yīng)用想法開始，然后將所有內(nèi)容都放入了私有數(shù)據(jù)庫中。 后來他們可能意識(shí)到，他們應(yīng)該改為使該應(yīng)用程序成為社交應(yīng)用程序。 將數(shù)據(jù)放入特定的數(shù)據(jù)庫后，遷移數(shù)據(jù)并不容易。

Permissions are usually an after thought

許可通常是事后的想法

Data security a priority in our company. But data security is not the first thing that comes to the mind of a developer. Especially when they’re just doing a proof-of-concept prototype. They want to focus on the functionality first, and take care of the security later on.

數(shù)據(jù)安全是我們公司的首要任務(wù)。 但是，數(shù)據(jù)安全性并不是開發(fā)人員想到的第一件事。 尤其是當(dāng)他們只是在做概念驗(yàn)證原型時(shí)。 他們想先關(guān)注功能，然后再注意安全性。

我們的外賣 (Our takeaways)

We are always thinking about how we could make our products better. We could do better in terms of software architecture, user documentation and ease-of-use. We sometimes brainstorm what we would do if we could rewind the clock two years to start over. But here is what we would tell our former selves:

我們一直在思考如何使我們的產(chǎn)品更好。 我們可以在軟件體系結(jié)構(gòu)，用戶文檔和易用性方面做得更好。 有時(shí)我們會(huì)集思廣益，如果我們可以倒退時(shí)鐘以重新開始兩年。 但是，這就是我們要告訴我們以前的自我：

If developers are already familiar with an existing concept, adopt it

如果開發(fā)人員已經(jīng)熟悉現(xiàn)有概念，則采用它

Most developers are familiar with the concept of a database. It is a container of some sort where developers can save content. They can also retrieve data and support the CRUD (Create, Read, Update, and Delete ) property.

大多數(shù)開發(fā)人員都熟悉數(shù)據(jù)庫的概念。 它是開發(fā)人員可以保存內(nèi)容的某種容器。 他們還可以檢索數(shù)據(jù)并支持CRUD(創(chuàng)建，讀取，更新和刪除)屬性。

Because developers are already familiar with the concept of a database, they would find a single database on Cloud DB straight-forward to use.

因?yàn)殚_發(fā)人員已經(jīng)熟悉數(shù)據(jù)庫的概念，所以他們可以直接在Cloud DB上找到一個(gè)數(shù)據(jù)庫來使用。

Introduce new concepts when developers are prepared for them

在開發(fā)人員為新概念做好準(zhǔn)備時(shí)引入新概念

This idea is actually an other way of saying that we should make the learning curve as easy as possible. Skygear was a prototype in its own way. We just launched V

這個(gè)想法實(shí)際上是說我們應(yīng)該使學(xué)習(xí)曲線盡可能容易的另一種說法。 Skygear本身就是一個(gè)原型。 我們剛剛推出了V

1.0!.

1.0 ！。

You never want to make life for your early adopters difficult. Having to learn everything before developers can do anything does not work well from a product perspective. Until developers need to think about data permission, they should not need to know about the difference between a private DB and public DB. We should let our users get started with the common concepts first to familiarize themselves with a new platform.

您永遠(yuǎn)都不想讓早期采用者的生活變得困難。 從產(chǎn)品的角度來看，必須學(xué)習(xí)所有知識(shí)之后開發(fā)人員才能做任何事情。 除非開發(fā)人員需要考慮數(shù)據(jù)許可權(quán)，否則他們無需了解私有數(shù)據(jù)庫和公共數(shù)據(jù)庫之間的區(qū)別。 我們應(yīng)該首先讓用戶開始使用通用概念，以熟悉新平臺(tái)。

Only after they’re comfortable should we introduce new concepts to provide more options. In this case, there’s no harm for a developer to discover they need ACL so the new concept is a natural next step after they have learned how to use Cloud DB.

只有在他們感到舒適之后，我們才可以引入新概念來提供更多選擇。 在這種情況下，對(duì)于開發(fā)人員來說發(fā)現(xiàn)他們需要ACL并沒有什么害處，因此，新概念是學(xué)習(xí)了如何使用Cloud DB之后自然而然的下一步。

我們學(xué)到了什么 (What we learned)

When we began working on Skygear two years ago, we wanted to build a kick-ass product with 2–4 of our senior developers. We had ready testers from our own in-house developers, who gave lots of critical feedback. We thought we were using our experience in web and mobile app development to make better decisions on how to design tools for other developers.

兩年前，當(dāng)我們開始從事Skygear的開發(fā)時(shí)，我們想與2-4位高級(jí)開發(fā)人員一起開發(fā)踢球產(chǎn)品。 我們有自己的內(nèi)部開發(fā)人員準(zhǔn)備的測試人員，他們提供了許多關(guān)鍵的反饋。 我們認(rèn)為我們正在利用我們?cè)赪eb和移動(dòng)應(yīng)用程序開發(fā)方面的經(jīng)驗(yàn)來就如何為其他開發(fā)人員設(shè)計(jì)工具做出更好的決策。

But our experience also created assumptions about what to expect our users to know before using our product.

但是，我們的經(jīng)驗(yàn)還為用戶在使用我們的產(chǎn)品之前應(yīng)了解的知識(shí)做出了假設(shè)。

The good thing about getting user feedback on Cloud DB as we went was that we learned that our assumptions were incorrect. Our most valuable lesson was the humbling reminder of a basic startup principle. No matter our experience, we often don’t know exactly what we’re building.

在進(jìn)行過程中獲得有關(guān)Cloud DB的用戶反饋的好處是，我們了解到我們的假設(shè)是錯(cuò)誤的。 我們最有價(jià)值的一課是謙卑地提醒人們一個(gè)基本的啟動(dòng)原則。 不管我們的經(jīng)驗(yàn)如何，我們通常都不完全知道我們要構(gòu)建什么。

Of course, that doesn’t stop us from trying to build that philosopher’s stone to make lives easier for our fellow developers anyway. As my co-founder, Ben, said one of his most productive days was when he tossed 1000 lines of code away.

當(dāng)然，這并不能阻止我們嘗試建立哲學(xué)家的石頭，以使??我們的其他開發(fā)人員的生活更加輕松。 正如我的聯(lián)合創(chuàng)始人本(Ben)所說，他最富有成效的日子之一是他丟掉了1000行代碼。

I would like to credit my colleague cheungpat who worked on the Cloud DB with me and helped write this piece.

我想感謝我的同事cheungpat和我一起在Cloud DB上工作，并幫助撰寫了這篇文章。

My team would love to hear your critical feedback for Skygear. Also check out our documentation and GitHub repos to see how we discuss Skygear features.

我的團(tuán)隊(duì)很想聽聽您對(duì)Skygear的重要反饋。 另請(qǐng)查看我們的文檔和GitHub存儲(chǔ)庫，以了解我們?nèi)绾斡懻揝kygear功能。

翻譯自: https://www.freecodecamp.org/news/how-to-handle-unknowns-and-make-assumptions-when-designing-a-cloud-database-df002068a83b/

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