User-specified chains and row versions in a blockchain table

One or more computer-readable non-transitory media storing one or more sequences of instructions that, when executed by computing devices, cause:

• defining a first blockchain database object that includes:
• a blockchain key that includes a field of said first blockchain database object;
• a sequence number field;
• a blockchain hash field;
• storing a plurality of user blockchains in said first blockchain database object, wherein each user blockchain of the plurality of user blockchains contains a respective plurality of records in said first blockchain database object, wherein each record contained in said user blockchain stores an identical blockchain key value in said blockchain key;
• storing a respective series of sequence numbers for each user blockchain of said plurality of user blockchains in said sequence number field, wherein each record in said each user blockchain that is not a first appended record in said each user blockchain:
• stores a particular sequence number of said respective series of sequence numbers of said each user blockchain in the sequence number field, the particular sequence number specifying an order in which each record was appended to said user blockchain;
• and
• holds a cryptographic hash value in the blockchain hash field that cryptographically links said each record to a previous record in said user blockchain that holds a sequence number in said sequence number field that is consecutive and previous to another sequence number held in said sequence number field of said each record.