i need to create a customised table "Employee" in which i have to insert employeeid,employeename and salary...on inserting the salary,the table should automatically calculate Hra(10% of basic salary),DA(9% of basic salary) and hence calculate net salary...so...plz guide me...how to do this?

how to do this

Don't. Do not store calculated values in your database. If Hra and DA are percentages of another database field, create a view which calculates them instead of storing them.

but how can i calculate values in a view???
can u plz show me thru some example...plz...i need to complete this by today otherwise my teacher will screw me...plz guide me

You need to crate a view and add the calculated values as columns.

HRA = salary * 10/100
DA = salary * 9 /100
net = HRA + DA

i still didnt get u...need an example...plz read my above query carefully

commented: you need to read carefully, don't expext to be spoon feed here. -2

create view xyz as 
select *, salary * 10 / 100 as HRA, salary * 9/100 as DA, salary * 19/100 as net from employees