Nothing about two-tier architecture prevents you from keeping clients in sync, scaling up or implementing business logic.
Consider that scaling your database has to be done anyway. Your web app will bottleneck on the DB too. The only difference is number of connections assuming you keep them open (but there are multiplexers for that, and many business apps don't need them anyway, RAM is cheap enough).
With stored procedures you can implement whatever logic is needed for maintaining your data.
Consider that scaling your database has to be done anyway. Your web app will bottleneck on the DB too. The only difference is number of connections assuming you keep them open (but there are multiplexers for that, and many business apps don't need them anyway, RAM is cheap enough).
With stored procedures you can implement whatever logic is needed for maintaining your data.