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Jan 30, 2022 8 tweets 3 min read Read on X
Types of keys in SQL

A thread🧵
📌Primary key
A primary key is a table attribute or column that identifies every record present in a table uniquely. There can be only one primary key attribute in a table and primary key column attributes can't be the same or null values. Image
📌Super key
It is the set of all columns which helps to identify rows in a table uniquely. Image
📌Candidate key
The candidate key is a column or set of columns that can qualify as a primary key in the database. There can be multiple candidate keys in a table and only one candidate key can qualify as a primary key. Image
📌Composite key
It is the set of two or more attributes that helps to identify each tuple in a table uniquely. Any key such as super, primary, candidate key, etc can be called a composite key if it has more than one attribute. Image
📌Foreign key
The foreign key is a key used to link two tables together. This is also called as referencing. Image
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More from @meetjain74

Aug 2, 2022
Consensus Mechanism in Blockchain

A thread🧵
📌Blockchain
Blockchain is a distributed decentralized network that provides immutability, privacy, security, and transparency. There is no central authority present to validate and verify the transactions.
Hence we require some consensus protocol.
📌What does consensus means?
A general agreement that is accepted by all people in a group.

In Blockchain, consensus refers to that all nodes in the network reach a particular agreement about the blocks in the blockchain
Read 18 tweets
Mar 24, 2022
NFT Use cases

A thread🧵 Image
🎵Music
Your unique musical artwork can be sold in the form of NFT to anyone. The owner has the right to determine how the composition is used.
🎮Gaming
NFTs have the best use case in the gaming world. Unique characters or avatars or items in the game can be bought and sold using NFTs. Example - purchasing weapons for the game via an NFT marketplace to play in the game.
Read 20 tweets
Feb 25, 2022
What are DApps?

A mega thread🧵
Most of the apps today run on centralized networks i.e they are controlled by a single authority. For example, social media networks, banks, and streaming services hold all of our data on centralized servers.
When you access any of these apps, a request is sent to the server and you gets a response back. Suppose you entered your credentials details to login into that system as a request and the response comes in form of access to the website or not(in case of invalid credentials).
Read 31 tweets
Feb 24, 2022
What is Defi?

A mega thread🧵 Image
Defi stands for 'Decentralized finance'. It refers to financial applications built on blockchain technology that enable digital transactions between multiple parties.

Before diving into it further, let us first understand centralized or traditional finance.
📌Example scenario
Suppose a person named Luv has some money and he wants to earn interest on that money. What will he do?

You are right!
He will deposit it in any bank and earn interest on that.
Read 92 tweets
Feb 22, 2022
What is the metaverse?

A mega thread🧵
Imagine that you and your friend physically far apart attending a 'Justin Bieber' concert 'virtually' with thousands of fans from across the globe together.

No, I don’t mean being part of an online concert of the like we have all attended in the pandemic times.
I am talking of virtual concerts in the Metaverse, which will be much more immersive than listening to a live video.

How do these events take place?

The event organizers can imagine how the concert would look…they will transport you to a beach, the moon, or some fantasy world.
Read 29 tweets

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