title: Master data and transaction data relations in hyperledger composer/fabric
body: <p>I want my master data and transaction data to always match. The master data is off-chain and the transaction data on-chain. </p>
  
  <p>The master data consists of several records from several tables. I want the transaction data to always match the master data. My participants are trusted, but it could be that one could go rogue and adapt the off-chain master data.</p>
  
  <p>I know that hashing is the way to go here. I see loads of examples that a string is hashed. But I am not sure how to hash multiple records. Do I put them all into an object, convert that into a string and hash it? Is there a cleaner way to do this? </p>