Create XML file from Oracle DB

Question

Hi,
I'm working in a task to create electronic billing for Mexico Rules, to do this; I need to create a XML source that will contain all the information requested from Oracle DB.
For this reason, I'm looking how to create this XML file from Oracle DB.
All this is for the new legislations rules in Mexico to use electronic billing.
Please, if you have any reference about this, let me know.
Thanks and regards.

Answer 1

you may want to check out commands like xmlforest and xmlelement
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/functions221.htm
copied from documentation
Purpose
XMLForest converts each of its argument parameters to XML, and then returns an XML fragment that is the concatenation of these converted arguments.
•If value_expr is a scalar expression, then you can omit the AS clause, and Oracle Database uses the column name as the element name.
•If value_expr is an object type or collection, then the AS clause is mandatory, and Oracle uses the specified c_alias as the enclosing tag. The c_alias can be up to 4000 characters.
•If value_expr is null, then no element is created for that value_expr.
Examples
The following example creates an Emp element for a subset of employees, with nested employee_id, last_name, and salary elements as the contents of Emp:
SELECT XMLELEMENT("Emp",
XMLFOREST(e.employee_id, e.last_name, e.salary))
"Emp Element"
FROM employees e WHERE employee_id = 204;
Emp Element
<Emp>
<EMPLOYEE_ID>204</EMPLOYEE_ID>
<LAST_NAME>Baer</LAST_NAME>
<SALARY>10000</SALARY>
</Emp>