Blockchain Developer Certification Practice

What kind of database structure is generally used for Ethereum's state storage?

1. Relational Database

2. Graph Database

3. Serialized Hash Data Structure

4. Flat File Database

The correct answer is: Serialized Hash Data Structure

Ethereum utilizes a serialized hash data structure for its state storage, which is essential for maintaining its decentralized nature and ensuring the integrity of data. This structure, known as a Merkle tree or specifically a Patricia Merkle Trie in Ethereum, allows for efficient storage and retrieval of the state of accounts and contracts. Each node in the trie represents a unique state or account, with hash functions providing security through cryptographic means. The use of a serialized hash data structure enables Ethereum to track changes and verify states compactly and efficiently. When a state change occurs, only the impacted parts of the data structure need to be updated, which minimizes the amount of data that needs to be stored and checked. This method also facilitates quick verification of data integrity, as one can trace back through the hashes to confirm that no tampering or unauthorized changes have occurred. In contrast, while other database structures like relational databases, graph databases, and flat file databases have their own advantages in specific contexts, they do not meet the needs of Ethereum's architecture as effectively as the serialized hash data structure. This specialized approach is key to supporting Ethereum's functions, including transaction verification, smart contract execution, and overall decentralized governance.