System-versioned system-time tables are typically used for regulatory and compliance purposes, and for keeping a table-resident history of database operations on the table data. Consequently, most types of ALTER TABLE changes to these tables are not allowed. However, ALTER TABLE can be used to remove system versioning. After system versioning has been removed from a temporal table, the table becomes a regular nontemporal table, and all normal ALTER TABLE operations are permitted.
Use the following ALTER TABLE syntax to remove system versioning from a system-time table:
ALTER TABLE your_system_time_table DROP SYSTEM VERSIONING;
Where your_system_time_table is the name of a system-versioned system-time table.
To drop the system-time columns, including the derived period column and its component beginning and ending bound TIMESTAMP columns, use the following ALTER TABLE syntax:
ALTER TABLE your_system_time_table DROP PERIOD FOR SYSTEM_TIME;
Where, again, your_system_time_table is the name of a system-versioned system-time table.
Dropping the system-time derived period column will automatically drop the two component columns.