This example modifies a table to add a derived period column.
Here is the table definition for this example.
CREATE TABLE employee ( eid INTEGER NOT NULL, name VARCHAR(100) NOT NULL, deptno INTEGER NOT NULL, jobstart DATE NOT NULL, jobend DATE NOT NULL ) PRIMARY INDEX(eid);
This following statement modifies the table, employee, to add a derived period column, jobduration, with jobstart as the period start column and jobend as the period end column.
ALTER TABLE employee ADD PERIOD FOR jobduration(jobstart, jobend);