Temporal syntax for ALTER TABLE allows you to create ANSI temporal valid-time tables from existing tables. It can be used to modify existing tables that may have already been created having DateTime columns that manually track the effective period during which information in the row is effective.
Adding valid time to the table involves these ALTER TABLE operations:
- Adding or altering the two DateTime columns that will serve as the beginning and ending bounds of the valid-time period
- Adding a valid-time derived period column to the table, and designating the derived period column VALIDTIME