record linking to each other in PL/SQL Developer - oracle

Question

There was a need to create records in PL / SQL Developer, which refer to each other. I started to understand all this recently, therefore there were doubts about the achievement of this goal, but also the thought was spinning in my head that I was not the first to ask this question. Therefore, if you know how to do it or have ideas for implementation, I will be very glad of your help, but for now I will continue to google.
Example:
TYPE rtype1 IS RECORD
(
/*some code*/
r_type2 rtype2;
);
TYPE rtype2 IS RECORD
(
/*some code*/
r_type1 rtype1;
);
Additional Information:
The fact is that, on the basis of xsd schemes, you need to generate records and collections, but because In the xsd scheme this is not prohibited, such a need has arisen. And it is necessary to create types, and not to use the tools for working with xml.

Answer 1

You can use forward declaration to declare the existence of a type in PL/SQL before you fully specify it. Like this:
DECLARE
TYPE rtype2; -- Forward declaration
TYPE rtype1 IS RECORD( r_type2 rtype2 );
TYPE rtype2 IS RECORD( r_type1 INTEGER );
BEGIN
NULL;
END;
/
However, you cannot use this to declare a non-REF mutually recursive type; if you try this:
DECLARE
TYPE rtype2;
TYPE rtype1 IS RECORD( r_type2 rtype2 );
TYPE rtype2 IS RECORD( r_type1 rtype1 );
BEGIN
NULL;
END;
/
Then you get the error:
ORA-06550: line 4, column 18:
PLS-00318: type "RTYPE2" is malformed because it is a non-REF mutually recursive type
ORA-06550: line 4, column 3:
PL/SQL: Item ignored
You can do it using object data types and a REF in the SQL scope:
CREATE TYPE otype1; -- Forward declaration
CREATE TYPE otype2 IS OBJECT( o_type1 REF otype1 );
CREATE OR REPLACE TYPE otype1 IS OBJECT( o_type2 otype2 );
But, again, if you try to use a non-REF mutually recursive type:
CREATE TYPE otype1;
CREATE TYPE otype2 IS OBJECT( o_type1 otype1 );
/* ORA-24344: success with compilation error */
CREATE TYPE otype1 IS OBJECT( o_type2 otype2 );
/* ORA-04055: Aborted: "OTYPE1" formed a non-REF mutually-dependent cycle with "OTYPE2". */
Then it doesn't work.
db<>fiddle here

Answer 2

Yes, you can define a type and then reference it in another type, which you define later in the code or on the system. However, as Alex asked, what are you trying to accomplish? -- Also contrary to what mathguy posted you can create and use types whose definitions are co-dependent. I do not recommend doing so, but ...
From the documentation:
An incomplete type is a type created by a forward type definition. It is called incomplete because it has a name but no attributes or methods. It can be referenced by other types, allowing you define types that refer to each other. However, you must fully specify the type before you can use it to create a table or an object column or a column of a nested table type.