Introduction to Data Management

Developing Applications With PATHWAY
6-8 15873 Tandem Computers Incorporated
NonStop SQL, for enabling server programs to define and manipulate data
structures in an effective and efficient way
Data Definition Language (DDL), for defining records and data items in
ENSCRIBE databases, and for generating messages
INSPECT, for interactively examining and modifying running screen programs
and server programs
VIEWPOINT, for allowing operators to interact simultaneously with multiple
Tandem products through a single convenient interface
Developing a
PATHWAY Application
A PATHWAY application is a set of programs that perform OLTP tasks under control
of the PATHWAY software. The application normally includes one or more screen
programs for handling the user’s interface at the terminal or workstation, and one or
more server programs for handling the database.
To develop a PATHWAY application, you customarily perform the basic steps
outlined as follows. Some of these steps, and the software they involve, were
illustrated earlier in Figure 6-2. By using PATHMAKER, of course, you can simplify
many of these steps and combine others into fewer steps.
1. Designing your application. This step includes dividing the work of the
application between requesters and servers. It also includes identifying which
transactions will be protected by TMF.
2. Designing your database. For this step, you can use either NonStop SQL or
ENSCRIBE. Here, you plan the logical design of your database, identifying the
fields to be included and their attributes and relationships to one another. You
also plan the physical design, selecting the proper file types and record keys for
each of the files in the database.
3. Writing screen programs. In this step, you design the screens that your application
will use and you code the screen programs that will support them in the SCREEN
COBOL language. In these programs, you can include statements that indicate
transactions to be protected by TMF. You compile the screen programs into object
code modules, using the SCREEN COBOL compiler.
4. Writing server programs. You code these programs using any of several
languages: COBOL85, COBOL 74, TAL, MUMPS, FORTRAN, C, Pascal, Ada,
BASIC, or TACL. (If you are developing your application with PATHMAKER,
you are limited to using only COBOL85.) You can embed NonStop SQL
statements to handle your data access requests.
5. Testing requesters and servers. You can test both requesters and servers in
isolation before integrating them into your PATHWAY application.