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Now before we're going to explore what exactly we're going

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to build in this core section,

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and before we are going to start planning how we build it,

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let me answer one important question.

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Why exactly is this section about connecting to a database,

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from inside our backend website code?

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Why not from the front end?

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Why not, why a JavaScript in the browser?

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Well, there is a rule,

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and I will explain why we have that rule in a second,

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but the rule is that you should not, not, connect to

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a database from inside your frontend JavaScript code.

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So not from inside the code that runs

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in the browser in the end.

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Now, why is that the case?

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The reason for that is, that since it runs in the browser,

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so in the end on the computers of your website visitors,

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that code, any JavaScript code that runs in the browser

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is in the end, exposed to your website visitors.

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Of course the average visitor will not see it.

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The average visitor will just see

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the result of that code being executed,

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but if you're a bit more experienced, like you already are,

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you could open the developer tools and in there,

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if you click through the different tabs and so on,

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you can also view the client side, so to browser side,

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to JavaScript code,

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that was loaded for a given website,

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and that is executed for that website.

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So any JavaScript code that's running in the browser

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can be viewed by the visitors of your website.

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And even more than that, it cannot just be viewed,

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visitors could also edit the code that runs in the browser.

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This feature exists for debugging reasons,

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so that if you are working on your own website,

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if you are developing a website,

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you could change the code in the browser

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to temporarily test a change,

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but that is something visitors can do themselves as well.

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Now, normally that is no problem,

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because if visitors added the code that runs on the website

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that was loaded for them, they can only hack themselves,

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they can't do any harm to you or to other visitors.

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But this changes if you start connecting to a database,

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from inside your client's side code,

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because then since that code is exposed and editable,

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the visitors of your website could, for example,

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look up your database credentials.

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So the username and password, with which you're connecting

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to the database, and they could also manipulate

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the queries that are executed,

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they could start deleting your tables,

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where the data in your tables, when they actually shouldn't

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be allowed to do so.

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That's why you don't want to have any code that interacts

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with your database in the client side, JavaScript code.

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That's why we instead, always do that on the backend.

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So in our server side JavaScript code with node JS,

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because that code runs on our servers that belong to us,

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the developer, and this code that runs on the server side,

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can't be viewed by the visitors of our website.

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That's really, really important.