7trigger.txt

create database lib;
use lib;
create table library(srno int(5),name varchar(40),author varchar(20),allowed_days int(5));
create table library_audit(srno int(5),old_all_days int(5),new_all_days int(5));

insert into library values    (1,'Database Systems','Abc',10),
                              (2,'System Programming','xyz',20),
                              (3,'Computer Network & Internet','qwe',18),
                              (4,'Project Management','rty',24),
                              (5,'Python for Data Analysis','asd',12);

select * from library;


delimiter //
create trigger tr1
before update on library
for each row
begin
insert into library_audit values(new.srno,old.allowed_days,new.allowed_days);
end //


update library set allowed_days=15 where srno=1; //
update library set allowed_days=13 where srno=3; // 

select * from library; //
select * from library_audit; //