Time travel: two-dimensional time with bitemporal data

Bitemporal data is a method that allows users to update one record and query its status as it changes through time. This technique can be used in various scenarios such as employee records, options trading, and auditing. The concept of bitemporal data is based on the Asserted Versioning Framework (AVF), which operates on data in two-dimensional time. Each row in a bitemporal table is associated with two temporal intervals: effective time and asserted time. Effective time defines when the data contained in a row is valid, while asserted time is the time period in which the data in the row is true. The pg_bitemporal project is an implementation of AVF that works using PostgreSQL.