Calculating age from birthday with oracle plsql trigger and insert the age in table

Question

i have a table

dates
(dob date,
age number(4)
);

I will insert a date of birth and a trigger will calculate the age and insert that age in

Answer 1

If you do it by a trigger the age is potentially wrong after one day. This is why saving the age in a database table is bad practice and nobody does that. What you need is a view.

create view person_age as
  select person_id, 
    floor(months_between(trunc(sysdate),birthdate)/12) as age
    from birthdays;

Look at the SQL Fiddle