Question

I have many cursors that all return rows with the same fields: a numeric ID field and an XMLType field. Every time I access one of these cursors (each cursor has now got its own function for access), I go through the same pattern:

--query behind cursor is designed to no more than one row.
for rec in c_someCursor(in_searchKey => local_search_key_value) loop
    v_id := rec.ID
    v_someXMLVar := rec.XMLDataField
end loop;

if v_someXMLVar is null then
    /* A bunch of mostly-standard error handling and logging goes here */
end if;

exception
    /* all cursor access functions have the same error-handling */
end;

As the pattern became more obvious, it made sense to centralize it in a single function:

    function fn_standardCursorAccess(in_cursor in t_xmlCursorType, in_alt in XMLType) return XMLType is
            v_XMLData XMLType;
        begin
            dbms_application_info.set_module(module_name => $$PLSQL_UNIT, action_name => 'fn_standardCursorAccess');
            loop
                fetch in_cursor
                    into v_XMLData;
                exit when in_cursor%notfound;
            end loop;
            /*some additional standard processing goes here*/
            return v_XML;
        exception
        /*standard exception handling happens here*/
    end;

The problem I’ve run into is in calling this function. I now have to call it like this:

open v_curs for select /*blah blah blah*/ where key_field = x and /*...*/;
v_data := fn_standardCursorAccess(v_curs,alt);
close v_curs;

What I’d like to do is call it like this:

open v_curs for c_getSomeData(x);
v_data := fn_standardCursorAccess(v_curs,alt);
close v_curs;

…reason being to minimize the amount of changes to my code (I don’t want to have to cut/paste all these cursors to the functions that depend on them, and in the case where multiple functions depend on the same cursor, I’ll have to wrap that in a new function).

Unfortunately, this does not work, Oracle returns an error saying

Error: PLS-00222: no function with name 'C_GETSOMEDATA' exists in this scope

Is what I’m trying to do even possible?

(Oracle version is 10.2)

EDIT:
I think a better way to describe what I’m doing is pass a reference to an explicit cursor to a function that will perform some common routines on the data returned by the cursor.
It appears that I cannot use an open-for statement with an explcit cursor, is there any other way to get a reference to an explicit cursor so I can pass that reference to a function? Maybe there is some other way I could approach this problem?

EDIT:
Copying and pasting from my earlier reply to R Van Rijn’s reply:

I tried declaring the cursor in the package specification, and referencing it with the package name: open v_curs for PKG.c_getSomeData(x);… This gives me a new error, saying that PKG.c_getSomeData must be a function or array to be used that way.

UPDATE:
I spoke to our DBA here, he says it is not possible to have a ref cursor point to an explicit cursor. It looks like I can’t do this after all. Bummer. 🙁

Answer 1

It appears that what I wanted to do (have an open-for statement reference an existing explicit cursor) is simply not allowed in Oracle. 🙁