CBDH Smart Contract Development Flashcards

What is a 'chaincode-to-chaincode' invocation in Hyperledger Fabric?

Answer: One chaincode invoking another chaincode on the same or different channel

Chaincode-to-chaincode invocation uses stub.InvokeChaincode() to call another deployed chaincode from within chaincode logic.

In Fabric chaincode, what does `stub.CreateCompositeKey(objectType, attributes)` help achieve?

Answer: Creates namespace-scoped keys to avoid collisions between different data types

CreateCompositeKey builds structured keys from an object type and attributes, preventing key collisions across different data categories.

Which Fabric 2.x lifecycle command makes an approved chaincode active on a channel?

Answer: peer lifecycle chaincode commit

The commit command finalizes the chaincode definition on the channel after sufficient organizations have approved it.

What event mechanism in Fabric chaincode allows clients to listen for transaction-generated notifications?

Answer: stub.SetEvent(name, payload)

SetEvent allows chaincode to embed a named event with a byte payload in the transaction, which clients can subscribe to via the event service.

What is the purpose of the `--collections-config` flag when committing chaincode in Fabric?

Answer: Specifies private data collection policies for the chaincode

The collections-config flag points to a JSON file defining private data collections, their membership policies, and data dissemination rules.

In Hyperledger Fabric, what does `stub.GetPrivateData(collection, key)` retrieve?

Answer: Data stored in a private data collection visible only to authorized organizations

GetPrivateData reads data from a named private data collection, which is only accessible to organizations included in the collection's policy.