Merging a collection into a table

Question

I have a table with some blank columns.
I take all the data from the table in a collection and then process the data to fill those empty columns.
Now i have the collection with all the valid data.
Is it possible to cast this same collection into a table and merge it again into the original table?
I am trying to do so, but there is an error saying "cant use local collection"...
Any help on this would be appreciated.

Answer 1

Thanks a lot for your suggestion.
I would like to give you an elaborate process.
I have a table ABC. Some columns of that table are empty. I need to get those filled using some other tables.
Firstly, using a cursor I fetch the records in a collection say V_ABC.
Now in a FOR loop, I am fetching the missing data from other tables for every record in the collection and setting it in the empty places in the collection V_ABC itself.
So finally i have the collection V_ABC which has complete data.
The FOR loop is now ended.
Now i try to merge this V_ABC into tale ABC like this:
MERGE INTO ABC abc
USING TABLE(CAST(V_ABC AS TT_ABC)) z
ON (abc.random_column_name = z.random_column_name)
WHEN MATCHED THEN
UPDATE
SET abc.initially_empty_column = z.initially_empty_column
The exact error is "Error: PLS-00642: local collection types not allowed in SQL statements".
I am forced to use PL-SQL because of performance issues.
Could you provide an alternate way?
I guess one way would be to create another empty collection and EXTENDing it and creating a replica of V_ABC. Then probably it will allow me to merge. But i m not sure.