Creating a Dataset

create_set.py

This sample creates and validates a vBase set.

Summary

A set is a collection of objects. A named set of data records is a dataset. Such datasets can implement any point-in-time (PIT) or bitemporal data and prove this provenance to third parties. The sample illustrates low-level vBase set operations. Low-level set operations expose all vBase features and provide the most control without the benefit of simplifying higher-level abstractions.

Detailed Description:

• Create a vBase object using a Web3 HTTP commitment service. The commitment service is a smart contract running on a blockchain. The initialization uses connection parameters specified in environment variables:

  vbc = VBaseClient.create_instance_from_env()

• Create the test set commitment. This operation records that the user with the above VBASE_COMMITMENT_SERVICE_PRIVATE_KEY has created the named dataset. Such commitments are used to validate that a given collection of user datasets is complete and mitigates Sybil attacks (https://en.wikipedia.org/wiki/Sybil_attack). Set creation is idempotent. Multiple creations will log multiple events, but a single set commitment will be recorded. The returned receipt contains information on the set commitment. It can be optionally retained to simplify subsequent validation. All receipts are also available via vBase indexing services. Since add_set() calls are idempotent, duplicate calls will be no-ops and will return empty receipts.

  receipt = vbc.add_named_set(SET_NAME)
  print("add_named_set() receipt:\n%s", pprint.pformat(receipt))

• Verify that a given set commitment exists for a given user. This will typically be called by the data consumer to verify a producer's claims about dataset provenance:

  assert vbc.user_named_set_exists(vbc.get_default_user(), SET_NAME)