Abstract: A blockchain object stores multiple user blockchains, each blockchain comprising an ordered set of records in the blockchain object. The records of a user blockchain have the same blockchain key value. Users can create multiple blockchains by establishing respective blockchain key values for the blockchains. Like blocks in a blockchain, the records in a user blockchain are ordered by a sequence of numbers that is specific to the user blockchain; each user blockchain has its own sequence of numbers. Each record in a user blockchain holds a sequence number in a field of the blockchain object. An efficient mechanism maintains and assigns a sequence number to a record when appended to a user blockchain.

Abstract: In Secure-Asynchronous Signing, when a record is inserted into a collection of records by a user, the user specifies a registered digital certificate to associate with the record. The digital certificate was previously registered by the user. To subsequently sign a record, the user provides a digital signature. The digital signature is validated using data in the record and a public key of the digital certificate that was associated with the row. Invalid digital signatures are detected and rejected regardless of how long afterward the attempt to sign the row occurs after inserting the row.

Abstract: Techniques described herein allow a standby DBMS to maintain consistency of results for transactions that include redirected DML commands without requiring the standby DBMS to delay execution of queries that do not require changed objects. Specifically, a standby session records DML target object (DTO) record with information regarding DML-changed objects and transaction information from the primary DBMS. Using DTO records, the standby DBMS ensures that results of any additional queries include changes made by the redirected DML commands without delaying execution of queries that do not access changed objects. If a target object in a standby query is in a DTO record, then query execution is delayed until the standby database is updated to the timestamp indicated in the DTO record. Thus, the delayed query has access to changes made by the DML command. Otherwise, the query is immediately executed without waiting for the standby database synchronization.