Postgres Trigger

[Anand Karia]

Hi All

I am new to postgres sql. I have a table namely "Status" having 3 columns
TranDate,VoucherNo,UserID.....

I want to fire a trigger that if any changes made into above table then a new entry must be added into another Audit table namely "Audit_Status" having same columns with additional column that shows which operation is fired. like if
Addition is made then action will show A.
Edition is made then action will show E.
Deletion is made then action will show D.

Can anybody help me out who is using postgres database, how to make triggers and functions using above columns and tables