Introduction to Data Management

Developing Applications With PATHMAKER
5-4 15873 Tandem Computers Incorporated
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PATHMAKER generates applications that run in the PATHWAY environment, where
TMF controls the consistency of each transaction and creates audit trails that promote
data integrity. Together with the GUARDIAN 90 operating system, PATHWAY
supports fault tolerance and transaction recovery during application execution.
PATHWAY applications can be developed without PATHMAKER, but the process is
longer and less convenient. Without PATHMAKER, you must do many tasks
manually before you can run your application. These tasks include coding all
portions of all requesters and servers, testing them, and integrating them into a
PATHWAY system configuration.
To develop an application with PATHMAKER, you need PATHMAKER plus the
standard data definition language (DDL), the requester development language
(SCREEN COBOL), the server development language (COBOL85), and the transaction
processing system (PATHWAY). Notice that PATHMAKER does not generate servers
in languages other than COBOL85.
In managing database structures, PATHMAKER can interact with either
NonStop SQL or ENSCRIBE. To protect transactions while they are in progress,
PATHMAKER applications can optionally use TMF.
Application Operation PATHMAKER generates applications for handling a variety of tasks. These
applications can be large or small, serve many users at many terminals or just a few
dedicated users, and handle geographically distributed or local data. Most
applications generally repeat the following operational cycle:
1. Display forms on an end user’s terminal screen; the end user fills in these forms to
specify information about a transaction
2. Accept a request from the end user to update the database with the information in
the forms, or to list information from the database
3. Access the database to record the transaction data (by modifying the database), or
to list data
4. In some cases, send information about the transaction to applications on other
computer systems
5. Acknowledge (to the end user) that the request has been processed and that the
application is ready to accept another request
6. Repeat the above steps for all requests from all end users.
This cycle is typical of most OLTP applications.