How do I insert into a table of REF's?

CREATE TYPE artist_table_type AS TABLE OF REF artist_type;
/                                                         

INSERT INTO track_table VALUES (                              
   1,                                                     
   'test title',                              开发者_StackOverflow社区            
   123,                                                   
   to_date('12-09-1989', 'dd-mm-yyyy'),                   
   artist_table_type(                                     
            -- What goes here???
   ),                                                     
   artist_table_type());  

I want to insert into this table a nested table of references to objects. Can I do this? Am I going to have to un-nest this table?

You can create a nested table within SQL by using the COLLECT and CAST functions. For instance, if you want to select artist objects from some other table based on some condition, I believe this should work:

INSERT INTO track_table
  SELECT
   1,
   'test title',
   123,
   to_date('12-09-1989', 'dd-mm-yyyy'),
   CAST(COLLECT(REF(artists)) AS artist_table_type)
   artist_table_type()
  FROM
   artists
  WHERE <whatever the condition is for selecting the appropriate artists>
  ;

INSERT INTO TABLE(this table is syntax dont think its name of the table..)

(SELECT t.nested_tbl_colm 
(nested_tbl_colm is nested table) 

FROM table_name t 
(table_name is the normal table whose one or more column is nested table here its nested_tbl_colm)  

WHERE t.tbl_colm= any input or conditions)

VALUES
(value to be inserted);

COMMIT;

Rest of the column will be inserted normally and the above code is used to insert into nested table. Let me know if you didn't understand.