Oracle: Select From Record Datatype - oracle

Question

I have a function that returns a record datatype (2 fields: ID and Name). How can I get at the data from a select statement?
Specifically, I am trying using an OracleCommand object attempting to get the object into my C# code. I initially tried ...
CALL FUNCTION_NAME() INTO :loRetVal
... but I get a data type error for whatever type I use. I have also tried ...
SELECT * FROM FUNCTION_NAME()
... and ...
SELECT * FROM TABLE ( FUNCTION_NAME() )
... to no avail. I guess I am looking for ...
SELECT * FROM RECORD ( FUNCTION_NAME() )
... which, of course, doesn't exist.
The only solution I have been able to come up with is to wrap this function call in another function call in which the outer function returns a TABLE of records containing this sole record. This, however, seems cumbersome and I am looking for a simpler method. Any help would be appreciated.
EDIT: Sorry, I have also tried SELECT FUNCTION_NAME() FROM DUAL.

Answer 1

A record datatype is a PL/SQL datatype. SQL doesn't know about it. That's probably why you are getting an error. See this example:
SQL> create package mypkg
2 as
3 type myrec is record
4 ( id int
5 , name varchar2(10)
6 );
7 function f return myrec;
8 end mypkg;
9 /
Package created.
SQL> create package body mypkg
2 as
3 function f return myrec
4 is
5 r myrec;
6 begin
7 r.id := 1;
8 r.name := 'test';
9 return r;
10 end f;
11 end mypkg;
12 /
Package body created.
SQL> desc mypkg
FUNCTION F RETURNS RECORD
ID NUMBER(38) OUT
NAME VARCHAR2(10) OUT
SQL> select mypkg.f from dual
2 /
select mypkg.f from dual
*
ERROR at line 1:
ORA-00902: invalid datatype
The error in SQL I was referring to.
You can call it from PL/SQL though:
SQL> declare
2 r mypkg.myrec;
3 begin
4 r := mypkg.f;
5 dbms_output.put_line(r.id);
6 dbms_output.put_line(r.name);
7 end;
8 /
1
test
PL/SQL procedure successfully completed.
If you want to use the function in SQL, then you can create a SQL objecttype. Note that calling your function directly from C# looks way more preferable than insisting on using SQL to do this. But just for the record:
SQL> drop package mypkg
2 /
Package dropped.
SQL> create type myobj is object
2 ( id int
3 , name varchar2(10)
4 );
5 /
Type created.
SQL> create package mypkg
2 as
3 function f return myobj;
4 end mypkg;
5 /
Package created.
SQL> create package body mypkg
2 as
3 function f return myobj
4 is
5 begin
6 return myobj(1,'test');
7 end f;
8 end mypkg;
9 /
Package body created.
SQL> select mypkg.f from dual
2 /
F(ID, NAME)
--------------------------------------------------------------
MYOBJ(1, 'test')
1 row selected.
Regards,
Rob.

Answer 2

I think this what you are looking for; to get the values out in a select statement:
select result.id as id, result.name
from ( select function() as result from dual);
Because your function returns a record an not a native type you can't use the standard methods. The if you want to get the actual record as an object into C# then you have do some reading on user defined types in the ODP .net documentation.
You could also wrap the function in another function that returns a ref cursor and that is used in C# in a more standard fashion.

Answer 3

Can you
CREATE TYPE <object name> AS TABLE OF <record type>
and use that directly in a SQL statement? I ask because I have a stored proc that I can not edit. The stored proc has an output variable that is record type that I have to reference in a SQL statement. I have already created a function to call the proc, but if I don't have to convert the record to type object that would be nice.
I would later call it like:
SELECT *
FROM TABLE( CAST( <function name>() as <object name>));

Answer 4

The formatting of my comment for Rob van Wijk is bad. To continue his thought.
-- create a collection type
CREATE TYPE myobj_tab AS TABLE OF myobj;
-- have the function return a collection type
CREATE OR REPLACE function f return myobj_tab
IS
objtab myobj_tab;
BEGIN
objtab := myobj_tab(myobj(1,'test'));
return objtab;
end f;
-- CAST it as a table and straight up select from it.
SELECT id, name FROM TABLE(CAST(f() AS myobj_tab));

Answer 5

I think you are looking for PIPELINED functionality:
CREATE TABLE test_table(tt_id INTEGER,tt_text VARCHAR2(40));
CREATE PACKAGE test_pkg IS
TYPE tp_rec IS RECORD(tt_id INTEGER,tt_text VARCHAR2(40));
TYPE tp_recs IS TABLE OF tp_rec;
FUNCTION test_func RETURN tp_recs PIPELINED;
FUNCTION test_func1 RETURN tp_recs PIPELINED;
FUNCTION test_func2(ivar INTEGER) RETURN tp_recs PIPELINED;
END;
/
CREATE OR REPLACE PACKAGE BODY test_pkg IS
FUNCTION test_func RETURN tp_recs PIPELINED
AS
currec tp_rec;
BEGIN
currec.tt_id := 1;
currec.tt_text := 'test1';
PIPE ROW(currec);
END;
FUNCTION test_func1 RETURN tp_recs PIPELINED
AS
currec tp_rec;
CURSOR t_cursor IS
SELECT * FROM test_table;
BEGIN
OPEN t_cursor;
LOOP
FETCH t_cursor INTO currec;
EXIT WHEN t_cursor%NOTFOUND;
PIPE ROW(currec);
END LOOP;
CLOSE t_cursor;
END;
FUNCTION test_func2(ivar INTEGER) RETURN tp_recs PIPELINED
AS
currec tp_rec;
BEGIN
SELECT * INTO currec FROM test_table WHERE tt_id = ivar;
PIPE ROW(currec);
END;
END;
/
BEGIN
INSERT INTO test_table VALUES(1,'test1');
INSERT INTO test_table VALUES(2,'test2');
INSERT INTO test_table VALUES(3,'test3');
COMMIT;
END;
/
SELECT * FROM TABLE(test_pkg.test_func());
SELECT * FROM TABLE(test_pkg.test_func1());
SELECT * FROM TABLE(test_pkg.test_func2(2));
The above code is tested, and should give you a good start on this. Just look up the PIPELINED keyword in Oracle for more information (assuming you are working with Oracle...)

Answer 6

Why do you need to use SQL at all? You might be able to just use a System.Data.CommandType.StoredProcedure to call the function.
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