Form on a SQL Query - doesn't work with SELECT * - bug or feature ?

Question

When I do this,
Create Page -> Page with Component -> Form -> Form on a SQL Query -> SELECT * FROM EMP
I do not get any items displayed and it creates a simple HTML region / page. Do we have to necessarily specify the column names ?
Iam looking at a way to see if any addition of columns in the table does not involve IT intervention in recreating the form.
When we try to create with Form on a SQL Query, then shouldn't it be similar to the Report where the same thing works, if I give SELECT function_returning_columns() from DUAL even then the same thing happens where it creates an ITEM called functions_returning_columns() it creates HTML region
I asked a related question with no answer :-( in
Dynamic Creation of Items in Runtime through Application UI

Answer 1

Hi Marc,
Thanks. I just tried something like this. Taking the EMP table example, (it doesn't matter which table), I created a region based on a Pl/Sql function returning SQL query
( I selected the vertical report template including nulls to display it like a form ) :
DECLARE
v_sql VARCHAR2(3000) ;
mn_idx NUMBER := 1 ;
BEGIN
v_sql := 'SELECT ' ;
FOR recs IN (SELECT * FROM ALL_TAB_COLUMNS WHERE TABLE_NAME = 'EMP' ORDER BY COLUMN_ID)
LOOP
v_sql := v_sql || 'HTMLDB_ITEM.TEXT(' || mn_idx || ',' ||
recs.column_name || ') ' || recs.column_name || ', ' ;
mn_idx := mn_idx + 1 ;
END LOOP ;
v_sql := SUBSTR(v_sql, 1, LENGTH(v_sql) -2) ;
v_sql := v_sql || ' FROM EMP WHERE EMPNO = 7369 ORDER BY 1 ' ;
RETURN v_sql ;
END ;
This allowed me to do my updates etc.., Then I created a button called 'Apply' and a process called 'update_changes' on button click and defined this:
DECLARE
v_sql varchar2(1000) ;
mn_ctr NUMBER := 1 ;
BEGIN
v_sql := 'BEGIN UPDATE EMP SET ' ;
FOR recs IN (select COLUMN_ID, COLUMN_NAME, DATA_TYPE
from all_tab_columns where table_name = 'EMP'
ORDER BY COLUMN_ID) loop
-- Make changes here if required- this is assuming 9 columns --
v_sql := v_sql || recs.column_name || ' = HTMLDB_APPLICATION.G_F0' || mn_ctr || '(1),' ;
mn_ctr := mn_ctr + 1;
end loop ;
v_sql := substr(v_sql, 1, length(v_sql) - 1) ;
v_sql := v_sql || ' WHERE EMPNO = 7369; END ;' ;
execute immediate (v_sql) ;
END ;
Since this is for example, I didn't include code for Checksum and hardcoded empno = condition and have provision for 9 columns. I made some changes and tried saving it and I was able to do it.
I altered the table to add a column / drop a column and when I relogin, Iam able to see the changes.
Can you tell me if there could be any drawbacks in this approach ?.