Name: 2019年律師用CS50--數據庫設計 (CS50 for Lawyers 2019 - Database Design)
Uploaded: 2021-01-14T10:44:43.000Z
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DAVID MALAN: We've seen how with languages like Python

程度副詞

can we implement business logic on a server and, even if we want,

And we've seen, on the browser side, the so-called client side,

how you can render information or data to users.

And with CSS can we style it, and with JavaScript can

But when building a business or any application that

is interacting with users, where is all that data being stored?

Well, if you're running your own small business,

Of course, spreadsheets, whether they're implemented

as Microsoft Excel, or Google Spreadsheets, or Apple Numbers,

generally stores data in rows and columns.

And if you're like me, you probably use that first row

to represent the names of the columns and the types of the data

And as you continue to add more and more data to that spreadsheet,

you probably, like me, continue to add row after row after row.

And meanwhile, if you've got so much data or so many different types of data

that it doesn't really belong in one sheet,

you might actually create a second sheet or a tab

along the bottom of the screen, for instance, in which you

So indeed, Microsoft Excel allows you to store data relationally, so to speak.

You might have one sheet with customer info, another sheet with invoices,

another sheet with products, or any number of other types of data.

And you can relate those to another by somehow having some commonality

among them, some identifier, some name, some customer ID or the like.

And so data that tends to be stored in rows and columns

And you can do this certainly in the cloud these days

as well with Google Docs, simply a web-based version of the same.

But when designing your spreadsheets, or more

generally, your data's schema, the design thereof,

there's a number of questions you need to consider.

Because whether using Excel, or Numbers, or Google Spreadsheets,

odds are you sometimes configure the columns to be displayed or formatted

Numbers might be displayed with or without commas.

Numbers might be displayed with dollar signs or some other symbol.

You might separate one field from another

So these are all configuration options in a spreadsheet that might

In fact, let's consider a sample spreadsheet

wherein I might want to represent users in some web application.

All of us have, of course, registered for websites or applications

And what are some of the questions you're asked?

Well, you might be asked for your user name by some application.

And perhaps if you're buying something, or registering

for something, or someone that needs to know a bit more about you,

perhaps they'll even ask you for your address, maybe your phone number,

So you can certainly imagine there being even other fields that you need.

But let's consider now what types of data each of these fields is.

Well, by definition, this should be a unique value that belongs to you

For instance, if I'm registering for a website

and that website is storing some data in, for instance, a spreadsheet,

I might ideally try to claim Malan if it's available.

My name meanwhile, of course, will be just

David Malan, which someone else can certainly have as well.

And that, too, will be stored in a column of its own.

And then my address, for instance, here on campus, 33 Oxford Street, Cambridge,

A phone number by which I can be reached, 617-495-5000.

well, we'll leave that blank just for now.

So notice how each of these pieces of data is just a little bit different.

Some of them even have some punctuation therein.

Now, you might or might not in a spreadsheet

care to display this data a bit differently.

Indeed, the only number that I'm sweeping under the rug

But hopefully I don't need one or more commas in that value.

So there isn't really any need for special formatting here.

But it turns out that when you're actually

building a website or software-based application,

you're probably not storing your data ultimately in just spreadsheets.

You might graduate eventually from being a small shop to needing more than just

Microsoft Excel, or Numbers, or even something

Well, you have more rows than those programs can generally handle.

In fact, on your own Mac or PC, odds are,

when opening up big files, whether a spreadsheet or any other document,

The computer might start to slow, and you

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2019年律師用CS50--數據庫設計 (CS50 for Lawyers 2019 - Database Design)

ultimately

context

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