Merge possible from nested table?

Question

I recently have started using the merge command for some of our standard 'upsert' procedures. The old design for inserts was coming from a Java web service that would send over a flat file, which in turn the Java would call an insert procedure n times while in a loop, and on each call the procedure would perform a single insert.
As you are probably already shaking your head, I realize this makes way too many database calls to be scalable and is poor design. So I now have modified the procedure to take a nested table as the input and I loop through the nested table and do all the inserts in a single procedure call. I now want to take advantage of bulk binding. I know there is the FORALL command, but I figured there was a way to do this with MERGE since the procedure does an update if a match is found instead. I didn't know if there is any syntax to do this as the oracle docs state the USING clause can be a table, view or subquery.
I am using Oracle 10gR2 and SQL Developer 3.x. This was my attempt:
CREATE TABLE merge_table
    t_id     NUMBER(9,0),
    t_desc   VARCHAR2(100)
CREATE OR REPLACE TYPE merge_type IS OBJECT
    type_id     NUMBER(9,0),
    type_desc   VARCHAR2(100)
CREATE OR REPLACE TYPE merge_list IS TABLE OF merge_type;
CREATE OR REPLACE PROCEDURE my_merge_proc(p_records IN merge_list)
AS
BEGIN
    MERGE INTO merge_table MT
    USING
        SELECT
            p_records.type_id,
            p_records.type_desc
        FROM DUAL
    ) D           
    ON
        MT.t_id = p_records.type_id
    WHEN MATCHED THEN UPDATE
    SET
        t_id   = p_records.type_id,
        t_desc = p_records.type_desc
    WHEN NOT MATCHED THEN INSERT
        t_id,
        t_desc
    VALUES
        p_records.type_id,
        p_records.type_desc
END;
show error
CLEAR SCREEN
SET SERVEROUTPUT ON
-- test script to execute procedure
DECLARE
    l_list merge_list := merge_list();
    l_size NUMBER(9,0) := 5;
BEGIN
    l_list.EXTEND(l_size);
    FOR i IN 1 .. l_size
    LOOP
        l_list(i) := merge_type(i,'desc ' || TO_CHAR(i));
    END LOOP;
    my_merge_proc(p_records => l_list);
END;
PROCEDURE my_merge_proc compiled
Warning: execution completed with warning
10/23          PLS-00302: component 'TYPE_DESC' must be declared
10/13          PL/SQL: ORA-00904: "P_RECORDS"."TYPE_DESC": invalid identifier
5/5            PL/SQL: SQL Statement ignoredI know the syntax isn't correct. How do I fix this or is it even possible to do what I am trying to do?

Answer 1

Ironically, after thinking about this for another 5 minutes the answer finally came to me after I had given up hope:
CREATE OR REPLACE PROCEDURE my_merge_proc(p_records IN merge_list)
AS
BEGIN
    MERGE INTO merge_table MT
    USING
        SELECT
            type_id,
            type_desc
        FROM TABLE(p_records)   -- change here
    ) R           
    ON
        MT.t_id = R.type_id
    WHEN MATCHED THEN UPDATE
    SET
        --MT.t_id   = R.type_id,  -- cannot update the same column from on clause
        MT.t_desc = R.type_desc
    WHEN NOT MATCHED THEN INSERT
        MT.t_id,
        MT.t_desc
    VALUES
        R.type_id,
        R.type_desc
END;
show error
PROCEDURE my_merge_proc compiled
No Errors.
-- I run my anonymous script block from above
anonymous block completed
select * from merge_table;
     T_ID T_DESC                                                                                            
        1 desc 1                                                                                              
        2 desc 2                                                                                              
        3 desc 3                                                                                              
        4 desc 4                                                                                              
        5 desc 5