Triggers to update same column upon insert

I am new to Oracle.

Ver 8.1.7

Is it possible to declare a trigger to update the same column which is being inserted upon.

For e.g.,

insert into table_a(field_a) values(1);

and then declare a trigger on table_a which will update the value of field_a to field_a + 100. In effect all values of field_a gets incremented by 100 automatically after every insert. Received on Thu Apr 17 2003 - 14:47:39 CDT