This is not how 3-tier works.
You are right about 2-tier:
1 - database service application (mysql) on a database server machine
2 - client applications, using (1) via the network. Can be on a client machine or the server machine.
3-tier works differently:
1 - database service application (mysql) on a database server machine
2 - business objects application, running on the database server machine or another physical machine. This is the gateway to the data in (1)
3 - client applications, using (2) via the network. Can be on a client machine or the (2) machine.
3-tier does NOT mean you run the database service application at another physical machine separated from the data itself.
The idea behind 3-tier, is that the client applications become thinner and the business logic is in (2), so that multiple clients (in different programming languages, for example) can use the same business logic and the business logic is centralized in (2) instead of on the clients.
Hope this helps.
Martijn Tonies
Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server
Upscene Productions
http://www.upscene.com
My thoughts:
http://blog.upscene.com/martijn/
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