Smart Contract Requirements and Architecture BBLC Practice Questions (Page 4)

Questions 16–20

1. 16application · medium

   A team is designing a smart contract to track product ownership transfers. Each product has a unique ID, and the contract must store the current owner and a timestamp of the last transfer. The expected volume is high, and gas costs are a concern. Which data-modeling approach is most gas-efficient for this use case?

   • AStore the entire transfer history in a single string variable encoded as JSON.
   • BStore the owner and timestamp in two separate mappings keyed by product ID.
   • CUse a struct with owner and timestamp fields, and store it in a mapping keyed by product ID.
   • DUse an array of structs and iterate through it to find the product ID on each transfer.
   Reveal Solution Discussion Select an answer first
2. 17expert · hard

   A team is designing a smart contract that manages a community fund. They want to prevent a compromised admin from draining the fund, but they also need to be able to upgrade the contract to fix bugs. Which combination of patterns best addresses both concerns?

   • AMake the contract immutable and rely on external audits.
   • BUse a role-based access control with a single admin role and no upgradeability.
   • CUse a multi-signature wallet for admin functions and a proxy pattern for upgrades.
   • DUse a single admin key and a time-lock on all functions.
   Reveal Solution Discussion Select an answer first
4. 18expert · hard

   A company is designing a decentralized marketplace where buyers and sellers trade digital goods. The system must handle escrow, dispute resolution, and delivery confirmation. The team is deciding between a single monolithic contract and a set of modular contracts. Which architectural choice is most appropriate and why?

   • AUse separate contracts for escrow, dispute resolution, and delivery, and have them interact through well-defined interfaces.
   • BUse a single monolithic contract to keep all logic in one place and reduce deployment costs.
   • CUse a single contract but store all data in external storage to reduce complexity.
   • DUse a single contract with a large fallback function to handle all types of transactions.
   Reveal Solution Discussion Select an answer first
5. 19application · medium

   A gaming dApp stores player scores and levels. The contract is called frequently, and the team wants to reduce gas costs. Which storage pattern is most gas-efficient?

   • AUse a single mapping from player address to a struct containing score and level.
   • BStore each player's data in a separate contract.
   • CStore score and level in two separate mappings.
   • DStore all player data in a large array and search for the player each time.
   Reveal Solution Discussion Select an answer first
6. 20foundation · easy

   In a high-level architecture diagram for a smart contract system that processes insurance claims, which component is responsible for triggering the contract's claim-submission function?

   • AThe smart contract's internal storage
   • BThe consensus algorithm of the network
   • CThe user-facing front-end application
   • DThe blockchain node that stores the contract bytecode
   Reveal Solution Discussion Select an answer first