Adding a Dataset Record

add_string_dataset_record.py

This sample creates a dataset comprising string records if one does not exist and adds a record to the dataset.

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 demonstrates the higher-order vBase dataset and string record abstractions that hide the details of the object and record content id (CID) calculation (hashing). This example builds on the create_set.py code and omits redundant comments.

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 dataset. If this is a new dataset, this operation records that the user with the above VBASE_COMMITMENT_SERVICE_PRIVATE_KEY has created the named dataset. Dataset creation is idempotent. If this is an existing dataset, the call is ignored. 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).

  ds = VBaseDataset(vbc, SET_NAME, VBaseStringObject)

• Add string record to the dataset. Records an object commitment for a set record. A set record commitment establishes that a dataset record with a given CID has existed at a given time for a given set.

  receipt = ds.add_record("TestRecord")

• 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 ds.verify_commitments()[0]