The modulo & is to make the alphabet circular, when you're at z come back at a example for alph[(i shift) % 26] with i=20 and shift=10 without modulo you'll like to reach index 30 in the.
Be sure that sql server service is running.
If sql server service is not running you can run it by:
Opening run window (window+r) and type services. msc.
Find the sql server and right.