  Blockchain is an emerging technology that has already enabled a wide range of
applications, from cryptocurrencies to digital asset management to supply
chains. Due to this surge of popularity, analyzing the data stored on
blockchains transpires as a new critical challenge in data science. To assist
data scientists in various analytic tasks on a blockchain, we provide a
systematic and comprehensive overview of the fundamental elements of blockchain
network models. We discuss how blockchain data can be abstracted as various
types of networks, and how such associated network abstractions can be further
used to reap important insights into the structure, organization, and
functionality of blockchains.
