Day[23] Delete from Database?

In many companies, the person who makes the most money is the database manager. On our fourth day of learning database, I learned why. Unlike almost anything else dealing with computers, there are things you can do to a database from which there is no coming back.

Today we learned about inserting, updating, and deleting. When you perform any of these functions, the ramifications are forever. There is no undo button to travel the programmer back to the time before the database was changed. If a client tells you delete certain files and then, the next day, tells you he needs the information back, it’s too late. It’s gone.

The reason for this is that there are databases so large (think Amazon, Facebook, ect) and which have so much information and so many transactions, that they could not keep legitimate records if nothing ever went away.

Conversely, very few things are ever deleted. The challenges in corrupting a database lie mostly in inserting information and updating it. But it is a rare day when something is erased from a database simply for the sake of erasing.

There are two reasons for this. The first is what I’ve already been talking about: deleting data is risky business. What if you need it again in the future? The second problem is slightly more nefarious. Data, it turns out, is money.

When you opt to stop receiving a monthly email from the gym to which you used to belong, you don’t get deleted from their database. Same thing when you change your shipping address with Amazon. That old one is still around. And when you cancel Netflix (I don’t know why you would actually do this, but for example’s sake) they keep your info forever. It’s their currency.

Instead of deleting, a bit key is included with each customer. When you decide to quit your relationship with a certain company, they flip this key to its off position and you are included in the monthly emails no more. But you aren’t deleted. You’re still there, in a dormant state, waiting to be turned back on, mined for information, or sold to the highest bidder.

Flipping the key to the off position is often referred to as being deleted, but it’s not the same. Not the same at all. The company still has it and will still use it in one way or another.

So, as Tom says, when Mark Zuckerberg claimed to Congress that he deleted his customer’s information when they quit Facebook, database managers from around the world pointed at the screen they were watching on and shouted “Liar!”