How to pass input value to the IN parameter in a function

Question

Hi ,
I'm new to pl/sql programming.
The below function is used inside a package and the package is invoked in visual studio.
The function uses 2 input parameters.
Out of which 'in_report_parameter_id' value comes thru job processor service 's job request.
The second IN paramter values are hard coded in the function.
I'm not able to understand this.
If the values are hard coded , how to make sure that only the hard coded values are the right ones?
Please anyone could explain to me?
I really dont have good idea about how to pass INPUT parameter to the functions or procedure
Is there any nice document which could give me good understanding about what are the ways or types we could pass values to the input parameter in subprograms?
thanks in advance.
CREATE OR REPLACE FUNCTION get_class_text_str
     in_report_parameter_id IN NUMBER,
     in_which                IN VARCHAR2 DEFAULT 'SELECT'
RETURN VARCHAR2
IS
         end_text            VARCHAR2 (50)   := '';
         my_class_text_str  VARCHAR2(10000) := '';
         my_class_value_str VARCHAR2(10000) := '';
     CURSOR class_text(c_1_text VARCHAR2, c_2_text VARCHAR2) IS
     SELECT c_1_text || report_parameters.report_parameter_value
                           || c_2_text
                           || report_parameters.report_parameter_value
                           || '" '
      FROM report_parameters
     WHERE report_parameters.report_parameter_id     = 3690
       AND report_parameters.report_parameter_group  = 'CLASS'
       AND report_parameters.report_parameter_name   = 'CLASS'
GROUP BY report_parameters.report_parameter_value
ORDER BY CAST(report_parameters.report_parameter_value AS NUMBER);
BEGIN
     IF (in_which = 'SUM') THEN     
          OPEN class_text ( 'SUM(NVL("Class ', '", 0)) "Class ' );
     ELSIF (in_which = 'PERC')THEN
          OPEN class_text ( 'ROUND((("Class ', '" / "Total") * 100), 2) "Class ' );
          end_text := ', DECODE("Total", -1, 0, 100) "Total" ';
     ELSE
          OPEN class_text ( 'SUM(DECODE(bin_id, ', ', bin_value, 0)) "Class ' );
     END IF;
     LOOP
          FETCH class_text INTO my_class_value_str;
          EXIT WHEN class_text%NOTFOUND;
          my_class_text_str := my_class_text_str || ', ' || my_class_value_str;
     END LOOP;
     CLOSE class_text;
     my_class_text_str := my_class_text_str || end_text;
     RETURN my_class_text_str;
END get_class_text_str;
/Edited by: user10641405 on Nov 19, 2009 8:16 AM
Edited by: user10641405 on Nov 19, 2009 8:30 AM

Answer 1

This is not a design I would use, but should work if coded properly. I would probably build a reference cursor query as text and use one open fetch and close.
You have 2 input parameters, in_report_parameter_id and in_which. I could not find where in_report_parameter_id was used in the program, but the value passed in for in_which is being used in IF logic to decide how to open the cursor. After the cursor is open rows are being fetched and eventually the cursor is closed.
The values in_which are compared to are hard-coded. It is the programmer's job to make sure the values listed are the right values and the actions taken are also correct. Your program is assuming that if the first 2 values are not encountered the third one listed is the one you want.
To pass input values to a procedure you merely provide the values as a literal or variable in the call, something like
whatever := get_class_text_str(1,'SELECT');