Original subtitles

‫Welcome back.

‫So we just left off with our friend Jeff, having a really hard time keeping track of orders, things

‫were getting bigger and bigger and harder and harder to manage just with a spreadsheet.

‫So we advised them that a database might be useful.

‫So how would Jeff implement a database, let's say, an Amazon?

‫Well, remember, a database is just software and hardware that holds that data and allows us to manipulate

‫that data.

‫So Jeff on his computer decides to install a database management system.

‫Let's say he picks PostgreSQL, he installs it, and then he starts putting the data that we had in

‫a spreadsheet into PostgreSQL, into a database.

‫Now, again, something that we're going to learn about throughout this course.

‫But for now, I've simplified the diagrams for us.

‫So now Amazon decides that we're going to use a database, not a spreadsheet, because our company is

‫growing.

‫So they start creating a different way to organize data.

‫That kind of looks like a spreadsheet, like an Excel sheet, but a little bit different.

‫One is we have customers that is each customer.

‫Now has a customer I.D., a unique customer ID that we can identify the customer with, so I'm customer

‫one Saulius to Brunos three MO is for the beauty of this is that if I ever moved, I have one location

‫where Jeff could look to see my new address.

‫So there's only one record of myself and my address.

‫So Jeff knows exactly where to ship my product.

‫Next, we create the products data.

‫So this is another table that we're creating and products just like customers.

‫Have an ID to uniquely identify them.

‫We have the description of the product, but also the price.

‫Again, if we ever add products to our company, to Amazon, then we can just add it all in one location

‫if we want to change the price or offer discounts.

‫We can change the price in one location.

‫Then, of course, we need our orders.

‫In order for us to make money with Amazon, we need to actually sell stuff.

‫So how do we keep track of orders?

‫Well, each order, just like we had with customers and products, are going to have a unique ID.

‫But this is the beauty of something like a database.

‫Older one who ordered the first order while customer I.D. is right here.

‫What's the customer ID want, so Andre ordered something.

‫This is when I ordered it.

‫What product did Andre Order?

‫Well, what's two product ID two is a toy duck.

‫OK, Andre ordered a toy duck and then the quantity is one.

‫So now I know exactly who ordered it, what product, how many, what the prices and also the address

‫to shipping.

‫Now pause the video and see if we can connect all of these relations for the rest of the three orders.

‫Once you're done, let's take a look at what we've just created.

‫We've essentially created relations, right, instead of having everything in one Excel sheet, we now

‫have these tables that link to one another.

‫Each table has a relation to one another.

‫For example, the customer IDs are matched over here.

‫We have the product ID that's matched over here.

‫All of these are related with one another connected.

‫And because there's only one location for us to change things, for example, let's say the address

‫changes, I know exactly where to update those customers.

‫I know exactly where to update the product or even the orders.

‫And this is one of the big things with the database's, especially when it comes to a relational database

‫where we're able to create large, massive amounts of data beyond what an Excel sheet might be able

‫to do, but also organize it in a way that is really intuitive, although it might be really hard for

‫you to understand how to look at this data right now for a computer when we start using things like,

‫well, a computer understands this a lot better than a confusing Excel sheet with many, many rows,

‫many, many cells that are not linked or connected properly.

‫So to finish off this video, I want you to go back to our playground over here and start seeing how

‫these tables are organized, for example, go to the orders table and try to figure out what this first

‫order was.

‫We see that there's an order I.D., there's a customer ID.

‫Find out who the customer is, who the employee is that sold this product and the shipwright, who's

‫the shipper?

‫Once you start to decipher tables like that, well, that's when things get more and more interesting.

‫Congratulations, we just managed to help Jeff become the superstar that he is now.

‫You're welcome, Jeff.

‫All right.

‫I'll see you in the next video.