Introduction to Data Management

Developing Applications With PATHMAKER
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Consistent Application
Modules
PATHMAKER promotes consistency among requesters, servers, and even among
different applications, resulting in applications that are easy to use and maintain. To
support this standardization, PATHMAKER allows an application developer to create
default requesters and servers that function as templates or models that other
application developers can copy and modify. These models can reduce duplicated
efforts and help ensure parallelism among modules. For example, a model requester
might have standard key assignments for the utility functions, such as the help key;
the model requester screen could furnish a layout to be followed in producing screens
for all requesters.
This kind of standarization helps end users learn an application; it is easy to become
familiar with common features that appear frequently within a user interface.
Standardization also helps programmers during application maintenance; it is easy to
maintain an application wherein similar tasks are performed in a similar way.
Integrated System
Dictionary
PATHMAKER builds its applications around an integrated system dictionary called
the project catalog. When you enter information about a project, PATHMAKER
creates the catalog to hold all the administrative information for your application. The
catalog includes: DDL objects, application screens, requesters, servers, portions of
servers called services, and configuration information.
If your database contains NonStop SQL tables, PATHMAKER reads their descriptions
directly from the appropriate NonStop SQL catalogs rather than from a dictionary.
Reports from the Catalog The project catalog serves as an information center for your application. Through the
ENFORM query language, you can request various reports based on information in
the catalog.
These reports provide a useful cross-reference for the application. They help you
manage programs by presenting lists of objects that show where changes can be made.
They also furnish documentation for the application. These reports cover information
about objects in the catalog, including requester components, elements of screens, and
service and server structure. For example, one report shows, for each service, which
requesters invoke that service. Other reports show all data items referred to by a
particular module (requester or server), or all modules that refer to a specific data
item.
Simplified Maintenance Because PATHMAKER uses the project catalog to keep track of the changes you make
to an application, maintaining a PATHMAKER application is an easy job. For
example, a change to a terminal screen often results in a change to the catalog; and,
when you change a data item definition in the catalog, a screen, server, requester, or
message that references the item can often use the new definition after the application
is recompiled. Catalog reports can help you determine where to make changes and to
assess their overall impact on your application.