To pass data from the program to the database, for example as parameters in a query, or to pass data from the database back to the program, the COBOL variables that are intended to contain this data need to be declared in specially marked sections, so the embedded SQL preprocessor is made aware of them.
This section starts with:
EXEC SQL BEGIN DECLARE SECTION END-EXEC.
and ends with:
EXEC SQL END DECLARE SECTION END-EXEC.
Between those lines, there must be normal COBOL variable declarations, such as:
01 INTX PIC S9(9) COMP VALUE 4. 01 FOO PIC X(15). 01 BAR PIC X(15).
As you can see, you can optionally assign an initial value to the variable. The variable's scope is determined by the location of its declaring section within the program.
You can have as many declare sections in a program as you like.
The declarations are also echoed to the output file as normal COBOL variables, so there's no need to declare them again. Variables that are not intended to be used in SQL commands can be declared normally outside these special sections.
The definition of a group item also must be listed inside a DECLARE section. Otherwise the preprocessor cannot handle these types since it does not know the definition.
