PL/SQL ( sorry about previous )

Hi,

I want to do the following within PRO*C. Select a value of a column from a table. The column name is not known until runtime. Also the names and the number of the other columns are not known until runtime. I have learned i could use a dynamic cursor for this purpose. I've tried the following code (PL/SQL).
The hostvariable holding the name of the column is :typename. The type of the column is known at runtime in :typedata. The following types are allowed : 0 = integer

				  1 = long
				  2 = string
				  3 = char

                         ORA-01405: fetched column value is NULL

Does anybody know why i get this message and what to do about it. I also want to know when a NULL was returned because this asks for a special treatement.
I suspect it has something to do with indicators but i don't have a clue of how i can use them in dynamic SQL.
Does someone know of a better way to solve the problem or know why my code isn't working please contact me via this news-group or E-MAIL  Please Help!                                    

 EXEC SQL EXECUTE
 DECLARE

	test integer;
	errornumber integer;

 BEGIN
	:source_cursor :=dbms_SQL.open_cursor;
	dbms_sql.parse ( :source_cursor, 'select ' || :typename ||
		' from scott.customerdata WHERE USERID = :USERID', 1 );
	DBMS_SQL.BIND_VARIABLE ( :source_cursor, ':USERID', :UID );
	if ( :typeofdata = '0' ) then
		DBMS_SQL.DEFINE_COLUMN ( :source_cursor, 1, :datainteger2 );
	end if;
	if (  :typeofdata = '1' ) then
		DBMS_SQL.DEFINE_COLUMN ( :source_cursor, 1, :datainteger4 );
	end if;
	if ( :typeofdata = '2' ) then
		DBMS_SQL.DEFINE_COLUMN ( :source_cursor, 1, :datastring, 255 );
	end if;
	if ( :typeofdata = '3' ) then
		DBMS_SQL.DEFINE_COLUMN ( :source_cursor, 1, :datachar, 1 );
	end if;
	test := DBMS_SQL.EXECUTE ( :source_cursor );
	if dbms_sql.fetch_rows( :source_cursor) > 0 then
	    	if ( :typeofdata = '0' ) then
DBMS_SQL.column_value ( :source_cursor,1, :datainteger2, errornumber, test );
	  	end if;
	    	if ( :typeofdata = '1' ) then
DBMS_SQL.column_value ( :source_cursor,1, :datainteger4, errornumber, test );
		end if;
		if ( :typeofdata = '2' ) then
DBMS_SQL.column_value ( :source_cursor,1, :datastring, errornumber, test );
		end if;
		if ( :typeofdata = '3' ) then
DBMS_SQL.column_value ( :source_cursor,1, :datachar, errornumber, test );
		end if;
	end if;
         dbms_sql.close_cursor ( :source_cursor );

Thanks fo reading this.

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|  Jan Timmermans		  |	e-mail:	jtimmerm_at_alpha.luc.ac.be  |

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