Security on the Hyperledger Fabric is enforced with digital signatures. All requests made to the fabric must be signed by users with appropriate enrolment certificates. Once user is enrolled, Node js application persist certificate in wallet for future usages.

Fabric Node SDKs provide default file system wallet for storing fabric certificate. File system wallet stores user certificate in folders. This approach does not provide required security and flexibility to maintain certificate like generation of new certificate for enrolled users (if any modification to blockchain network) or unregistering user from blockchain. File system wallet also impact scalability as production projects grow.

Fabric Node SDK provides a way to store certificates in Couch DB but not in Postgres. There is not direct provision to store enrolment certificates to Postgres database. Postgres database support SQL and NoSQL data storing and has strong community support. Postgres database provides more flexibility compared to Couch db. Also, PostgreSQL provides cost effective alternative. This pattern demonstrates how to use Postgre SQL db as Certificate Wallet using Nodejs SDK.