Frm-41380 error - cannot set the blocks query data source

Question

Fairly new forms so bare with me. I am creating a form based on one table. This table has one column that is a nested table.
table name: szrtime
table columns: szrtime_code, szrtime_styp_list
szrtime_styp_list is a table of varchar2(1).
main block is szvtime_block
the block that contains the nested table is szvtime_styp_block
I read that I could use a WHEN_NEW_RECORD_INSTANCE trigger on the main block to display the related nested table. I have tried the folllowing:
Declare
select_stmt Varchar2(512) ;
Begin
If :szvtime_block.szvtime_code Is not null Then
     select_stmt := '(SELECT column_value FROM TABLE ( SELECT szrtime_styp_list FROM szrtime WHERE szrtime_code = ''' || :SZVTIME_BLOCK.SZVTIME_CODE || '''))';
     Go_Block('SZVTIME_STYP_BLOCK' );
     Clear_Block ;
     message('select_stmt = '||select_stmt);
Set_Block_Property( 'SZVTIME_STYP_BLOCK', QUERY_DATA_SOURCE_NAME, select_stmt ) ;
Execute_Query ;
Go_Block('SZVTIME_BLOCK') ;
Else
Go_Block('SZVTIME_STYP_BLOCK' );
Clear_Block ;
Go_Block('SZVTIME_BLOCK') ;
End if ;
End ;
The result is the frm-41380 error.
I have tried change the query data source type on the nested table block to Table or From-clause but did not help. The select statement that is valid and returns the correct result in Toad.
Any suggestions on what to look for? Thank you.
Todd

Answer 1

> But what is giving me pause is that the user will be updating, deleting, and inserting
into this table and, of course, the nested table column.
It would give me pause, too. I've never used nested tables, so I poked around in Forms on-line help. In Forms 6i, it specifically states that Forms does not support the Nested Table structure.
In Forms 10g help, it describes Nested Table structures, but says NOTHING about how a form would handle it. And that implies to me that it is still not supported. So good luck.
In addition to creating the view, you may need to provide your own nested table updating procedures via a package on the server which your form can call. I know Forms supports passing pl/sql tables ("indexed by binary_integer"), so you could pass your nested table back and forth between the package and the form in that format.