Assuring Referential Integrity in Blockchain Applications

Blockchain technology is increasingly used for applications beyond cryptocurrencies and asset management. Taking advantage of its immutability, security, trustworthiness, auditability, reliability, and decentralized authority, these applications store rich data with nuanced internal structures, relationships, and constraints in the blockchain. Popular blockchain platforms provide very limited support for assuring logical data integrity. An important integrity constraint is the foreign key referential integrity (RI) originated from relational databases. This paper is among the first efforts on specifying and assuring RI in blockchain applications by proposing an effective JSON-based model and framework. It generalizes the concept of RI to the JSON object model, which can then be applied to document NoSQL databases as well as blockchain. The paper provides a typed graph model formulation for specifying blockchain assets and RI, and accompanying algorithms for RI assurance. A permeating application example is presented with an implementation using the proposed model in Hyperledger's Fabric, a permissioned blockchain platform.