Recording a last updated time for each record in a table

Question

hi
i have a table with 5 columns. and the table has 100 rows of data.
i need to add a sixth column and this column should contain the last updated time of that particular row.
i am allowed to use triggers.
for example, if the 55th row undergoes a change, the 6th column's value for the 55th row should update itself with that particular time.
can any one of you come up with an optimized solution for this please ???
thanx a million in advance and best regards,
novice DBA
:)

Answer 1

Hi,
Here's an example:
CREATE OR REPLACE TRIGGER table_x_biu
BEFORE INSERT OR UPDATE ON table_x
FOR EACH ROW
BEGIN
     :NEW.modified_dt := SYSDATE;
END     table_x_biu
SHOW ERRORSwhere table_x is your table name, and modified_dt is the DATE column to be populated.
You won't have to specify modified_dt in any INSERT or UPDATE statements. In fact, if you do, the value you give will be ignored, and the trigger will always substitute SYSDATE.
WARNING: if you do get an error message, the line number reported will usually be relative to the first DECLARE or BEGIN statement in the trigger. For example, if I had mis-spelled SYSDATE in the example above, the error message would say there was a problem in line 2, not line 5.