Marta Paes shows off a new feature in Apache Flink:
In the 1.7 release, Flink has introduced the concept of temporal tables into its streaming SQL and Table API: parameterized views on append-only tables — or, any table that only allows records to be inserted, never updated or deleted — that are interpreted as a changelog and keep data closely tied to time context, so that it can be interpreted as valid only within a specific period of time. Transforming a stream into a temporal table requires:
– Defining a primary key and a versioning field that can be used to keep track of the changes that happen over time;
– Exposing the stream as a temporal table function that maps each point in time to a static relation.
It looks pretty good.