Oracle triggers and how to directly modify the content of new rows

Create or replace trigger uptime
Before -- before must be used here
Insert on Table1
For each row -- for each row is Row-Level Trigger, but not Statement-Level Trigger. For example, if you use a statement to insert 10 entries to the table, the operation is triggered only once. For example, insert into Table1 select * From Table2 is triggered only once. Therefore, we generally use for each row. In addition, if it is triggered at the statement level, the columns: new. And: Old. cannot be used.

Begin
: New. Column 1: =: New. Column 2
End uptime;