COBOL ALLBASE/SQL application development involves the following steps:
Preprocess those programs in the application that contain SQL
commands.
Compile the preprocessed (modified) source code as well as any
source code not requiring preprocessing.
Run the resulting code (either intermediate or executable), as
discussed in the preceding chapter.
In the simplest case, the ALLBASE/SQL COBOL application is
derived from one source file. In other cases, the ALLBASE/SQL
COBOL application might consist of a source file main program
and one or more source file subprograms. These source files may
or may not contain SQL code. Only source files containing SQL
code need to be preprocessed, as illustrated in Figure 2-1.
During preprocessing, the COBOL preprocessor actually accesses
the same DBEnvironment to be used by your program at run time.
The preprocessor stores a module in the DBEnvironment which is
executed at run time. The module is used at run time to
optimize and validate DBEnvironment operations.
During any invocation, the COBOL preprocessor can access only
one DBEnvironment. You can create separate subprograms that
all access the same DBEnvironment. Each subprogram is
separately preprocessed and compiled. In this case, the
preprocessor stores multiple modules in one
DBEnvironment.
The criteria governing the division of an application program
into subprograms is very application-dependent. As in the
development of any application program, factors such as program
size, program complexity, expected recompilation frequency, and
number of programmers affect how a program is subdivided. In
the case of ALLBASE/SQL COBOL application programs, the
following factors should also be noted:
All code containing embedded SQL commands must be preprocessed.
The preprocessor can access only one DBEnvironment at a time.
Each program or subprogram (preprocessed unit) that accesses the
same DBEnvironment must have a unique OwnerName.ModuleName.
The preprocessor can process only one program or subprogram per
invocation.
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