You could also have a data layer that is responsible to connect to the database. That would provide more abstraction to the actual database being used. You could change the back end without much impact on the business layer.

You don't have to open and close the connection after each request. That depends on the use you make. If you have a lot of users (like a web server), you have advantage in keeping open a connection for the smallest time possible. If it's for a desktop application and you have enough licenses, you can keep the connection open longer to make the application faster. There is also the option of using a connection pooling with MTS.

HTH

>When doing n-tier development how do you guys handle the connection to the database?
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>Let's say my app is connecting to database on server A and the business logic tier is in server B.
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>Before in the client server world each workstation would run the EXE and establish 1 connection and use this connection thru the life of the application.
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>Now in the n-tier world the connection is being established at the business logic layer? Does that mean that's it's going to be opening and closing connections with each request?