As i understand, any piece of blockchain is comfirded every transaction in system and record it to new blockchain that unautorised transaction cannot be able be in new blockchain.
In central database you can cheat a lilbit and hide some information out of consensus and final product can’t present it.
It means that data needs to be globally accepted by everyone in the prosess. Everyone allong the way publishes their information that they know or their transactions. All of the data has to match up between all involved on the blockchain or a majority.
A central database is possible to be changed by one party. there is only one set of data. One party can change it and publish it as the truth without central validation.
What the truth is will be decided by the majority of participants with the right of deciding the truth. This established truth is the consensus. In terms of blockchain, the decision is based on the physically available data, the past and algorithms. But on the other hand, if the majority agrees on an altered or “false” database, that version becomes the new “truth”. In contrast to traditional databases, the data itself is defined as the truth without any (full) knowledge about how that data came into existance.
Compare Wikipedia to the Bible 
2, In a central database the one or ones that administer this database can add, change or delete data with some other ulterior goals in mind than the pure verification, that is used in Blockchain.
That the transactions will be verified by the by all the nodes in the network, the data needs to be coherent throughout the blockchain.
There’s no verification there’s trust.
It means that all the nodes in the network work together to verify the transaction that is asking for premission to be accepted by the blockchain. To achieve this, all the nodes in the network must be in agreement that the transaction meets all terms that is agreed up on. These terms are based on the copy that al nodes in the network have of the blockchain.
A single entity can alter, remove or add any data as they please in a central database. In a blockchain, it’s not possible for a single entity to alter or remove any date, you can only add. Al the data that is added to the blockchain also has to be accepted by the network of nodes.
Nodes heaving the same block of information in front of them gives the ability for the network to agree or disagree on what is stated by single entity therefore no mistake can be done or some false claims granted as me heaving a 1000 bitcoins.
The central database can be altered while blockchain database can not be.
1.The blocks have to be verified by the miners before they can be recorded.
2. Central database is not able to be verified by a group, it is private.
Consensus determines the truth because it is the agreement of all computers in the Blockchain network agreeing that a transaction is valid. If there was no consensus on a transaction, it would never be put into Blockchain in the first place.
In a centralized database, the truth can be manipulated by a central authority. In Blockchain, computers are incentivized to agree on a universal truth for transactions as it results in monetary gains when played by the rules.
Consensus determines the truth by the nodes all coming to an agreement together.
This is different from how truth is determined in a central database because that is based on the select information that is provided by the parties. It relies on trust.
Homework - Consensus
Benefits of Using Blockchain
What does it mean when we say that in blockchain, consensus determines the truth?
• Consensus determines truth because the blockchain works through a network of decentralization. Each node that verifies a transaction work in unity with each other to make sure that each transaction will be valid.
How is this different from how truth is determined in a central database?
• This is different than from how a central database works because there is no proof of validity. You basically have to trust that what you are getting (clothes, food, etc) is what the manufacturer says it is, or sourced from where they say it is sourced.
Enough nodes of the network have to agree (I suppose it depends on the particular network how many that is) on a status before it is considered the truth. This is mainly to prevent any bad actors from corrupting the state of the blockchain.
Central databases are subject to corruption/manipulation/alteration by anyone with write access to that database.
1. What does it mean when we say that in blockchain, consensus determines the truth?
Since the blockchain is decentralized, all nodes have a copy of the transaction record.
This allows all nodes to determine if a transaction is valid because it can be verified across the nodes.
This consensus is what provides verification of the transaction and keeps the transaction record as an authoratative source of truth.
2. How is this different from how truth is determined in a central database?
In a centralized database, the since the records can be modified coupled with a centralized administrator control, the records can change which means the transaction records can be altered. This allows an actor to determine truth of a transaction rather then verifying it because the transaction can be altered.
1. What does it mean when we say that in blockchain, consensus determines the truth?
Consensus in blockchain determines the truth by making every transaction be validated by every machine in the blockchain. Anyone who tries to lie and submit a invalid transaction will not be validated by the other machines in the blockchain.
2. How is this different from how truth is determined in a central database?
A central database can be manipulated by whoever is in control of it. Everyone has to trust that the information that is recorded is true.