Generating multi-level xml in oracle

Question

Hi,
I want to create a multi-level XML structure from oracle, is there a way?
Presently oracle provides DBMS_XMLQUERY and XMLGEN package to generated XML structure given a query. But the structure so generated is of single level. That is say I use
select XMLGEN.getXML('select * from employees') from dual;
the output is
<EMPLOYEE>
<ROW num="1">
<NAME>Mark</NAME>
<TEL>451-638191</TEL>
</ROW>
</EMPLOYEE>
That I call a single level output.
To create a multiple level XML I went in for object type in oracle. But the problem with this is that if I want to have multiple children for a single parent then object types fail. The structure below is not possible with object type.
<EMPLOYEE>
<ROW num="1">
<NAME>Mark</NAME>
<CONTACT>
<ROW>
<RESIDENCE>
<ADDRESS>
     <ROW>
     Fifth Avenue, New York
     </ROW>
</ADDRESS>
<TEL>
     <ROW>451-638191</ROW>
     <ROW>451-638192</ROW>
     <ROW>451-638193</ROW>
</TEL>
</RESIDENCE>
</ROW>
<ROW>
<RESIDENCE>
<ADDRESS>
     <ROW>
     Fouth Avenue, New York
     </ROW>
</ADDRESS>
<TEL>
     <ROW>452-638191</ROW>
     <ROW>452-638192</ROW>
     <ROW>452-638193</ROW>
</TEL>
</RESIDENCE>
</ROW>
</CONTACT>
</ROW>
</EMPLOYEE>
Then I tried nested tables. Here one needs to create an object type to create a table type. One cannot create a table type out of another table type. So that leavs me with 2 levels
object type
used by
table type
used by
table.
Presently to generated a multi-level output as shown above I'm using cursors and build it in a clob variable.
Is there any other way that one can build a multi-level structure. Or is there a build in package that comes with orace 8i (and higher).
Regards,
Milton.

Answer 1

Milton,
I was able to generate hierarchical XML from Oracle using object views and XML-SQL Utility (XSU).
Here is a simplified version of my OR schema:
/* Physical spec object */
create or replace type physical_specifications_object as object (
physical_specifications_id number(15),
page_count number(10),
product_id number(10),
four_color_count number(10),
two_color_count number(10),
table_count number(10),
binding_type varchar2(100),
height varchar2(20),
width varchar2(20)
/* Market object */
create or replace type market_object as object (
market_id number(15),
master_class_name varchar2(50),
market_name varchar2(100),
market_type varchar2(100),
market_description varchar2(500),
level_rank varchar2(15),
market_code varchar2(100),
product_id number(10)
/* List of markets */
create or replace type market_table as table of market_object;
/* Market object view */
create or replace view market_object_view of market_object
with object identifier (market_id) as
select mkt.market_id,
class.master_class_name,
mkt.market_name,
mkt.market_type,
mkt.market_description,
prod_mkt.level_rank,
mkt.market_code,
p.product_id
from market mkt,
product p,
product_market prod_mkt,
master_class class
where p.product_id = prod_mkt.product_id
and prod_mkt.market_id = mkt.market_id
and mkt.master_class_id = class.master_class_id(+);
/* Feature object */
create or replace type product_feature_object as object (
feature_id number(15),
feature_text varchar2(3500),
feature_type varchar2(100)
/* List of features */
create or replace type product_feature_table as table of product_feature_object;
/* Product object */
create or replace type product_object as object (
product_id number(10),
title varchar2(150),
media_type varchar2(20),
standard_number varchar2(100),
physical_specifications physical_specifications_object,
markets market_table,
product_features product_feature_table
/* Product object view */
create or replace view product_object_view of product_object
with object identifier (product_id) as
select p.product_id,
p.title,
p.media_type,
p.standard_number,
physical_specifications_object(spec.physical_specifications_id,
spec.page_count,
spec.product_id,
spec.four_color_count,
spec.two_color_count,
spec.table_count,
spec.binding_type,
spec.height,
spec.width),
cast(multiset(select *
from market_object_view mkt
where mkt.product_id(+) = p.product_id) as market_table) as markets,
cast(multiset(select f.feature_id, f.feature_text, f.feature_type
from feature f
where f.product_id = p.product_id) as product_feature_table) as product_features
from product p,
physical_specifications spec
where p.product_id = spec.product_id(+)
The objective is to generate XML for a product list with all the product subelements. The simple query "select * from product_object_view" when fed to the XML-SQL utility generates multi-level SQL. Note that Oracle 8i allows up to two level collection nesting in object types. Oracle 9i removes this limitation.
Check XSU documentation at http://otn.oracle.com/docs/tech/xml/xdk_java/doc_library/Production9i/doc/java/xsu/xsu_userguide.html#1014886
Hi,
I want to create a multi-level XML structure from oracle, is there a way?
Presently oracle provides DBMS_XMLQUERY and XMLGEN package to generated XML structure given a query. But the structure so generated is of single level. That is say I use
select XMLGEN.getXML('select * from employees') from dual;
the output is
<EMPLOYEE>
<ROW num="1">
<NAME>Mark</NAME>
<TEL>451-638191</TEL>
</ROW>
</EMPLOYEE>
That I call a single level output.
To create a multiple level XML I went in for object type in oracle. But the problem with this is that if I want to have multiple children for a single parent then object types fail. The structure below is not possible with object type.
<EMPLOYEE>
<ROW num="1">
<NAME>Mark</NAME>
<CONTACT>
<ROW>
<RESIDENCE>
<ADDRESS>
     <ROW>
     Fifth Avenue, New York
     </ROW>
</ADDRESS>
<TEL>
     <ROW>451-638191</ROW>
     <ROW>451-638192</ROW>
     <ROW>451-638193</ROW>
</TEL>
</RESIDENCE>
</ROW>
<ROW>
<RESIDENCE>
<ADDRESS>
     <ROW>
     Fouth Avenue, New York
     </ROW>
</ADDRESS>
<TEL>
     <ROW>452-638191</ROW>
     <ROW>452-638192</ROW>
     <ROW>452-638193</ROW>
</TEL>
</RESIDENCE>
</ROW>
</CONTACT>
</ROW>
</EMPLOYEE>
Then I tried nested tables. Here one needs to create an object type to create a table type. One cannot create a table type out of another table type. So that leavs me with 2 levels
object type
used by
table type
used by
table.
Presently to generated a multi-level output as shown above I'm using cursors and build it in a clob variable.
Is there any other way that one can build a multi-level structure. Or is there a build in package that comes with orace 8i (and higher).
Regards,
Milton.