17.05 - System-Time Modifications - Teradata Database

Teradata Vantageā„¢ - ANSI Temporal Table Support

Advanced SQL Engine
Teradata Database
June 2020
Programming Reference

Temporal modifications to system-time columns are straightforward and entirely automatic. They are not influenced by the nature of the modification.

  • When a row is deleted from a system-time table, the row is not physically deleted from the table. The end of the system-time period of the row is set to the time of the deletion, and the row becomes a closed row. It no longer participates in most SQL operations on the table, but remains in the table as a historical record of what existed in the past.
  • When a row is modified in a system-time table, the end of the system-time period of the row is set to the time of the modification, closing the row, and a copy of the row with the modified data is inserted into the table. The system-time period of the new row begins at the time of the modification, and ends at UNTIL_CLOSED. The new row is active in the database and can participate in SQL operations.

For more information on modifying ANSI system-time tables, see Modifying Rows in ANSI System-Time Tables.