Oracles! What are they? And why do we need them in Ethereum?
One of the major benefits that we have on Ethereum is that the Smart Contracts are running on a Sand Box and they can’t do http codes, and can’t access hardware layers. It’s basically a bunch of codes that are executed once a transaction is sent.
I will enlighten you more of what it really means, by running a hands-on example directly from Remix. In the examples I will give you, we will be doing an app that runs binary options according to the temperature in Vienna, Austria with a 24-hour expiry date at the time of purchase. The app will bet according to the temperature of Vienna in 24 hours, let’s say, if the temperature is more than 10 degrees then we win, if it’s lesser then the Smart Contract wins. It may sound difficult but in this video I will demonstrate the most simplest form of that. As a result, I’d like to give you some clarity where Oracles come in, and what are its drawbacks and benefits.
Check out the code on GitHub here: https://gist.github.com/tomw1808/ef21d73b4eaf06618a3ccd67ea6152a4
Grab a copy of Thomas Wiener's book here: Ethereum Blockchain Developer