Dynamic fields and conditions

Question

Hi!
I have created a tabular form with:
1. Fields that users can use to filter the table
2. Filter button to filter the data
3. Fields where they select the column name, input the value for update
4. Update button that updates the filtered data in a dynamic PL\SQL
I have a set SQL query on the report that always checks all the values, so I need to have nvl function in case users don't fill all the fields.
Problem with this is that the query lasts very long.
Another problem is, that since I have max 3 columns for update; in case they don't fill those columns, update doesn't work.
Is it possible to maybe create fields in a dynamic way like it is default on a report?
And does anyone know how I could solve the problem with the update in case users select just one column name and fill just one value for update?
Regards,
Ivan

Answer 1

It is possible to dynamically generate PL/SQL. Your problem is, you need to generate the entire program. So, if you are manipulating PL/SQL tables in your dynamic SQL you need to declare those tables and populate them in the dynamic code. Although, I suppose you could pass PL/SQL tables as parameters to EXECUTE IMMEDIATE, I've never tried. Either way, I foresee a gnarly piece of code coming up. I'm glad I don't have to maintain it.
In the following example I shall ignore all considerations of PL/SQL tables, etc. In other words, it won't work but it will give you the idea.
plsql_stmt := 'DECLARE l1 number; l2 number; l3 number; l4 number; BEGIN '
plsql_stmt := plsql_stmt||' l1 := :1; l2 := :2; l3 := :3;';
FOR lrec IN ( SELECT rownum AS r, field_1, field_2, math_op, do_something FROM rules )
LOOP
   IF lrec.r != 1
   THEN
      plsql_stmt := plsql_stmt||'ELSIF ';
   ELSE
      plsql_stmt := plsql_stmt||'IF ';
   END IF;
   plsql_stmt := plsql_stmt||lrec.field_1||' '||lrec.math_op||' '||lrec.field_2;
   plsql_stmt := plsql_stmt||' THEN '||lrec.do_something||' ;';
END LOOP;
plsql_stmt := plsql_stmt||' END IF; :4 := l4; END;';
EXECUTE IMMEDIATE plsql_stmt USING ln_abc, ln_def, ln_ghi, ln_result;
...Good luck, APC