-- https://docs.oracle.com/en/database/oracle/oracle-database/23/adjsn/using-pl-sql-object-types-json.html
DECLARE
  je JSON_ELEMENT_T;
  jo JSON_OBJECT_T;
BEGIN
  je := JSON_ELEMENT_T.parse('{"name":"Radio controlled plane"}');
  IF (je.is_Object) THEN
    jo := treat(je AS JSON_OBJECT_T);
    jo.put('price', 149.99);
  END IF;
  DBMS_OUTPUT.put_line(je.to_string);
END;
/