Bitcoin Forum

Are mutable blockchains, blockchains or databases?

What makes a blockchain "a blockchain", and what makes "a blockchain" a database? Is there a technical answer to it, or is it philosophical?

I have read/listened to many debates about it, but it never arrived to a "correct answer". Is there an actual correct answer?

I see blockchain as a special format of database. Imho all blockchains are databases.
But at the point a blockchain is made mutable, it may not be beneficial for the project to use blockchain at all.

I've seen a post here that may give more details (with the same conclusion though) : https://bitcoin.stackexchange.com/questions/77313/does-it-make-sense-to-design-a-mutable-blockchain

In principle, Blockchain is repository of information that is distributed, permissionless, immutable and transparent, with inherent redundancy and cryptographic security by design. The core value that it provides is transparency and immutability, from which trust is derived. Now if we make the blockchain mutable, as I see it, it breaks the trust value, making it "another thing".

That does not convert it into a Database, at least in the traditional sense, since it still lacks the essential properties of requiring permissions and admin, being generally centralized, speed per physical TX, and so forth.

A mutable Blockchain seems to be in no man’s land, closer to Blockchain by design, but lacking to meet the core values that one expects on a Blockchain.

I am still not understand with blockchain and what does mean by blockchain and what for using blockchain, I only understand with bitcoin and altcoin because its the way how to get much profit with investing and trading, I don't take care with blockchain feature and function in real life.

The main feature of blockchain is that blocks are linked together via hashing and pointing to the previous block. Blockchain is definitely a data structure, it even has some similarities to a linked list, but calling it a database is a question of semantics. For example, Bitcoin uses Google's LevelDB internally, so you could argue that blockchain is not a self-sufficient database software akin to MySQL.

I'd say you could still call mutable blockchains blockchains, because that's still what they're trying to emulate anyway. They'd still be closer in both function and form to run-of-the-mill blockchains than traditional databases. That being said, I don't see the point, and I wouldn't be surprised if they ceased to exist in the future. There was a CW piece that tackled this a while back:


Another reason why I'm fine with calling them blockchains is because language is inherently fluid anyway; words change depending on their usage. For as long as people call them blockchains (and they do), the definition of the term will be adjusted to accommodate them.