A database system stores data in a bi-temporal index that maintains recordation time and a validity time for recorded values. The index for a given key may be append only, such that the stored data for the key doesn't require modification of previously-recorded data for given validity times. The bi-temporal index comprises a key-value data store that allows values to be recorded for a specific key, validity time, and recordation time. To retrieve a value, a request presents a query with a key, subject time, and observation time. Queries look for values with a validity time most recent to and before the queried subject time and a recordation time, associated with the validity time, most recent to and before the queried observation time. The queries prioritize the validity time over the recordation time and returns the value that satisfies the query request.
展开▼
