Need help on simple cursor

Question

Hi All,
I am trying to list name of columns based on input table names
Not sure why below simple code is not working
Can you please suggest what is wrong?
SQL>declare
  2  v_list varchar2(200);
  3  cursor c1 (i_table_name varchar2) is
  4  select * from all_tab_columns where
  5  owner='SCOTT' and table_name in i_table_name;
  6  begin
  7  v_list := '(''DEPT'')';
  8  dbms_output.put_line(v_list);
  9  FOR rec in c1(v_list)
10  loop
11  dbms_output.put_line(rec.column_name);
12  end loop;
13  end;
14  /
('DEPT')
PL/SQL procedure successfully completed.

Answer 1

There is a fundamental concept you are missing.
You define a STRING variable:
v_list varchar2(200);
It is NOT a list. It is a single value string variable.
Then you attempt to use a literal string value as a list:
select * from all_tab_columns where  owner='SCOTT' and table_name in i_table_name;
Putting 5 words in to a string does not make it a list:
v_list varchar2(200) := 'word1,word2,word3,word4,word5';
A list needs to be defined as an ARRAY type:
type TStringArray is table of varchar2(30);
stringList TStringArray;
An array consists of cells or items. Which means a list of 5 items will be an array of 5 items:
stringList := new TStringArray( 'word1','word2','word3','word4','word5');
This is a basic data structure concept in programming. And you need to understand it fully BEFORE writing a single code statement. It is that critical to understand. Programming is all about manipulating data structures. Not commands and statements.