Using the Resource Manager, you associate URIs with the operations on
transactions (begin, commit, and rollback). When a user invokes one of these URIs,
the corresponding transaction operation is performed by the ResourceManager.
These URIs can be mapped to stored procedures that
display appropriate pages to the user. For example, the begin transaction URI
could display to the user a list of items to add to his or her shopping cart, the
commit transaction URI could display to the user a list of purchased items, and
the rollback transaction URI could display to the user a page that asks if he wants
to drop the existing shopping cart and start another one.

Between the begin and the commit or rollback URI, the user invokes other URIs that
call procedures to perform some action on the database. These procedures might or
might not belong to a transaction. If the URI belongs to a transaction, the actions
performed by that procedure would be committed or rolled back when the transaction
ends. If the URI does not belong to the transaction, it is not affected by the
transaction, and Prism treats it as a regular request (changes made by that URI are
committed upon completion).
URIs belonging to a transaction usually invoke procedures
within a package.

The sequence of URIs for a stored procedures within the database when invoked
would look like the following:

-- begin a transaction
http://host:port/servlet/demo/test.txn_begin

-- the first operation in the transaction
http://host:port/servlet/demo/test.txn_update1

-- the second operation in the transaction
http://host:port/servlet/demo/test.txn_update2

-- some more operations

-- commit the transaction
http://host:port/servlet/demo/test.txn_commit