Howto develop OO apps using ProC/C++ 2.2?

From: Sandy Ryan <sandyryan_at_hfx.andara.com>
Date: Fri, 02 Apr 1999 15:20:33 -0400
Message-ID: <37051881.E903704D_at_hfx.andara.com>

Does anyone know how to use ProC/C++ to write C++ applications?
Here's my problem.

I have an "employee" class that has a single method "getSalary" which simply does a select from an emp table and returns the salary of the employee with the specified employee number.

I want to separate the interface from the implementation for this class by putting the interface in a file called "emp.h" and the implementation in a file called "emp.cc" (generated by ProC/C++ from "emp.pc").

I create a 3rd file called "main.cc" containing the main function which simply declares an instance of the employee class and invokes its "getSalary" method.

Both main.cc and emp.cc need to #include "emp.h".

Now here's the problem ...
My employee class should contain data members which correspond to the rows in the emp table. These will include things like VARCHARS. Do I have to parse my ".h" header file with the ProC/C++ precompiler? If not, how can I get the proc compiler to recognize the host variables in the EXEC SQL SELECT of the getSalary method in emp.pc?

I guess the bigger question is this:
Do I have to have to declare host variables in a special "EXEC SQL BEGIN DECLARE SECTION" ?
If not, is it sufficient to just stick a colon in front of these variables and call them "host variables"?
 

Pseudocode ...

/******************************************************************************/
main.cc:
    #include emp.h

    int
    main(void)
    {
        emp employees;
        cout << "Salary = " << employees.getSalary("7439") << endl;
    }

/******************************************************************************/
emp.h:
    class emp
    {
        /* Does this go here? */
        EXEC SQL BEGIN DECLARE SECTION;
        ...
        EXEC SQL END DECLARE SECTION;

        /* Or can I do this... ? */
        int empno;
        struct {
            unsigned short len,
            unsigned char arr[20]
        }ename;
        float salary;

        public:
            emp();
            float getSalara(int empno);
    }

/******************************************************************************/
emp.pc: (--> emp.cc)
    emp()
    {
        ...
        empno = 0;
        ename.arr[0] = '\0';
        salary = 0.0;
        ..
    }

    getSalary(int empno)
    {
        ...
        SELECT  sal
        INTO :salary
        FROM emp
        WHERE empno=:emp_number;
        ...
    }

/******************************************************************************/ Received on Fri Apr 02 1999 - 21:20:33 CEST