I tried prisma deploy . It shows the changes are applied. But when I check in my prisma service, the database has not been changed. How can I apply the datamodel.prisma changes to the database as well ?

How are you checking the database? Are you using the Databrowser? Prisma Admin has a bug right now that doesn’t pick up those applied changes. If you clear the local storage key Prisma Admin or go incognito it should show any new changes

Yes, I'm using Databrowser. So, I think that may be the issue