Blockchain By Example

Smart contract data location

Although each smart contract has its own separate storage space, we do not decouple the storage-layer code from the other layers of the application as we do in classical development methods. Therefore, there is no querying language, such as SQL, or separated database component, but the smart contract through its code provides the ability to initiate permanent states, and read or store data.

As we introduced in the previous chapter, Peer-to-Peer Auctions in Ethereum, the smart contract is executed in the EVM to update the system state. This virtual machine provides dedicated storage, which is a persistent associative map where the contract stores states (permanent data). It also provides volatile memory to hold ...