Blockchain CBDH Practice Test - Questions Answers, Page 12

Rich Query Language capability is available with CouchDB. What DB is used? The ledger system in Hyperledger fabric uses levelDB. By definition, LevelDB allows concurrent writers to safely insert data into the database by providing internal synchronization State database options include LevelDB and CouchDB. LevelDB is the default key-value state database embedded in the peer process. CouchDB is an optional alternative external state database. (Binary data) https://hyperledger-fabric.readthedocs.io/en/release-1.3/fabric_model.html

Values can be assigned to any field variable A CTO file consists of:

• A single namespace, in which all resource declarations are implicitly.

• The overall “model” defines the representation of assets.

• A set of resource definitions that includes assets, transactions, participants, and events.

• Values may be assigned to any field variable.

• The option to import resources from other namespaces.

• When using composer modeling language, the words “asset” and “participant” are reserved.? Asset ownership instance is defined in a relationship field. (symbol: o) ? The modeling language does not support multiple inheritance.

Peers are connected to the channel and can receive all the transactions that are broadcasted on that channel. Consensus takes place within a channel by members of the channel only. Channels are membership based.

Reference: https://hyperledger-fabric.readthedocs.io/en/release-1.3/channels.html

Reputation Manager is part of the MSP Membership services provide identity, privacy, and confidentiality to the network. Basic access to the network is determined through the role of the member, who may all have separate legal and/or independent entities. Depending on the network, different authentication schemes are used for assigning identity. For transacting, the participants must obtain identities. The Reputation Manager enables auditors to view transactions pertaining to a participant, providing that each auditor has been granted proper access authority, based on the role of the participants.

When the Init, Invoke or Query function of a chaincode is called, the fabric passes the stub *shim.ChaincodeStub parameter. This stub can be used to call APIs to access to the ledger services, transaction context, or to invoke other chaincodes.

Reference: https://fabric-docs-test.readthedocs.io/en/latest/API/ChaincodeAPI/

Reference: https://godoc.org/github.com/hyperledger/fabric/core/chaincode/shim#ChaincodeStub.PutState

Business Network Archive: Capturing the core data in a business network including the business model, transaction logic, and access controls, the Business Network Archive packages these elements up and deploys them to a runtime. Stored as “.bna” files.

Reference: https://godoc.org/github.com/hyperledger/fabric/core/chaincode/shim#ChaincodeStub.PutState

The security module works in conjunction with the membership service module to provide access control service to any data recorded and business logic deployed on a chain network.