亚洲免费在线-亚洲免费在线播放-亚洲免费在线观看-亚洲免费在线观看视频-亚洲免费在线看-亚洲免费在线视频

Don’t Delete – Just Don’t

系統(tǒng) 1703 0

Don’t Delete – Just Don’t

Tuesday, September 1st, 2009.

Don’t Delete – Just Don’t
After reading Ayende’s post advocating against “soft deletes” I felt that I should add a bit more to the topic as there were some important business semantics missing. As developers discuss the pertinence of using an IsDeleted column in the database to mark deletion, and the way this relates to reporting and auditing concerns is weighed, the core domain concepts rarely get a mention. Let’s first understand the business scenarios we’re modeling, the why behind them, before delving into the how of implementation.

The real world doesn’t cascade

Let’s say our marketing department decides to delete an item from the catalog. Should all previous orders containing that item just disappear? And cascading farther, should all invoices for those orders be deleted as well? Going on, would we have to redo the company’s profit and loss statements?

Heaven forbid.

So, is Ayende wrong? Do we really need soft deletes after all?

On the one hand, we don’t want to leave our database in an inconsistent state with invoices pointing to non-existent orders, but on the other hand, our users did ask us to delete an entity.

Or did they?

When all you have is a hammer…

We’ve been exposing users to entity-based interfaces with “create, read, update, delete” semantics in them for so long that they have started presenting us requirements using that same language, even though it’s an extremely poor fit.

Instead of accepting “delete” as a normal user action, let’s go into why users “delete” stuff, and what they actually intend to do.

The guys in marketing can’t actually make all physical instances of a product disappear – nor would they want to. In talking with these users, we might discover that their intent is quite different:

“What I mean by ‘delete’ is that the product should be discontinued. We don’t want to sell this line of product anymore. We want to get rid of the inventory we have, but not order any more from our supplier. The product shouldn’t appear any more when customers do a product search or category listing, but the guys in the warehouse will still need to manage these items in the interim. It’s much shorter to just say ‘delete’ though.”

There seem to be quite a few interesting business rules and processes there, but nothing that looks like it could be solved by a single database column.

Model the task, not the data

Looking back at the story our friend from marketing told us, his intent is to discontinue the product – not to delete it in any technical sense of the word. As such, we probably should provide a more explicit representation of this task in the user interface than just selecting a row in some grid and clicking the ‘delete’ button (and “Are you sure?” isn’t it).

As we broaden our perspective to more parts of the system, we see this same pattern repeating:

Orders aren’t deleted – they’re cancelled. There may also be fees incurred if the order is canceled too late.

Employees aren’t deleted – they’re fired (or possibly retired). A compensation package often needs to be handled.

Jobs aren’t deleted – they’re filled (or their requisition is revoked).

In all cases, the thing we should focus on is the task the user wishes to perform, rather than on the technical action to be performed on one entity or another. In almost all cases, more than one entity needs to be considered.

Statuses

In all the examples above, what we see is a replacement of the technical action ‘delete’ with a relevant business action. At the entity level, instead of having a (hidden) technical WasDeleted status, we see an explicit business status that users need to be aware of.

The manager of the warehouse needs to know that a product is discontinued so that they don’t order any more stock from the supplier. In today’s world of retail with Vendor Managed Inventory, this often happens together with a modification to an agreement with the vendor, or possibly a cancellation of that agreement.

This isn’t just a case of transactional or reporting boundaries – users in different contexts need to see different things at different times as the status changes to reflect the entity’s place in the business lifecycle. Customers shouldn’t see discontinued products at all. Warehouse workers should, that is, until the corresponding Stock Keeping Unit (SKU) has been revoked (another status) after we’ve sold all the inventory we wanted (and maybe returned the rest back to the supplier).

Rules and Validation

When looking at the world through over-simplified-delete-glasses, we may consider the logic dictating when we can delete to be quite simple: do some role-based-security checks, check that the entity exists, delete. Piece of cake.

The real world is a bigger, more complicated cake.

Let’s consider deleting an order, or rather, canceling it. On top of the regular security checks, we’ve got some rules to consider:

If the order has already been delivered, check if the customer isn’t happy with what they got, and go about returning the order.

If the order contained products “made to order”, charge the customer for a portion (or all) of the order (based on other rules).

And more…

Deciding what the next status should be may very well depend on the current business status of the entity. Deciding if that change of state is allowed is context and time specific – at one point in time the task may have been allowed, but later not. The logic here is not necessarily entirely related to the entity being “deleted” – there may be other entities which need to be checked, and whose status may also need to be changed as well.

Summary

I know that some of you are thinking, “my system isn’t that complex – we can just delete and be done with it”.

My question to you would be, have you asked your users why they’re deleting things? Have you asked them about additional statuses and rules dictating how entities move as groups between them? You don’t want the success of your project to be undermined by that kind of unfounded assumption, do you?

The reason we’re given budgets to build business applications is because of the richness in business rules and statuses that ultimately provide value to users and a competitive advantage to the business. If that value wasn’t there, wouldn’t we be serving our users better by just giving them Microsoft Access?

In closing, given that you’re not giving your users MS Access, don’t think about deleting entities. Look for the reason why. Understand the different statuses that entities move between. Ask which users need to care about which status. I know it doesn’t show up as nicely on your resume as “3 years WXF”, but “saved the company $4 million in wasted inventory” does speak volumes.

One last sentence: Don’t delete. Just don’t.

??

Don’t Delete – Just Don’t


更多文章、技術(shù)交流、商務(wù)合作、聯(lián)系博主

微信掃碼或搜索:z360901061

微信掃一掃加我為好友

QQ號聯(lián)系: 360901061

您的支持是博主寫作最大的動力,如果您喜歡我的文章,感覺我的文章對您有幫助,請用微信掃描下面二維碼支持博主2元、5元、10元、20元等您想捐的金額吧,狠狠點(diǎn)擊下面給點(diǎn)支持吧,站長非常感激您!手機(jī)微信長按不能支付解決辦法:請將微信支付二維碼保存到相冊,切換到微信,然后點(diǎn)擊微信右上角掃一掃功能,選擇支付二維碼完成支付。

【本文對您有幫助就好】

您的支持是博主寫作最大的動力,如果您喜歡我的文章,感覺我的文章對您有幫助,請用微信掃描上面二維碼支持博主2元、5元、10元、自定義金額等您想捐的金額吧,站長會非常 感謝您的哦!!!

發(fā)表我的評論
最新評論 總共0條評論
主站蜘蛛池模板: 久久久精彩视频 | 日本最新免费二区 | 欧美日韩免费做爰视频 | 在线亚洲精品视频 | 婷婷综合色伊人阁 | 亚洲精品日韩中文字幕久久久 | 久久777国产线看观看精品卜 | 在线午夜 | 亚洲福利精品一区二区三区 | 久久精品国产乱子伦多人 | 奇米色奇米 | 日本久久网 | 日日骑夜夜骑 | 5060网一级毛片免费观看 | 国产精品欧美亚洲韩国日本不卡 | 亚洲综合欧美在线 | 国产91在线免费观看 | 精品国产免费一区二区 | 亚洲一区二区三区久久久久 | 无夜精品久久久久久 | xxxx免费国产在线视频 | 国产亚洲精品久久久久久久网站 | 在线免费观看中文字幕 | 99re视频精品全部免费 | 久久一本久综合久久爱 | 日本毛片大全 | 99热这里只有精品第一页 | 国产精品免费一区二区三区 | 久久99精品国产99久久 | 一级毛片区 | 久久精品香蕉视频 | 天天操天天操天天操 | 波多野结衣久久精品 | 精品煌色视频网站在线观看 | 九九久久国产精品 | 亚洲欧美不卡中文字幕 | 欧美亚洲另类图片 | 成人久久18免费网址 | 91麻豆精品国产91久久久久久 | 国产一区二区高清在线 | 亚洲欧美日韩国产 |