Hi,
Is it possible to build an XML (or JSON) document using a map database columns to XPath expressions? For example:
root > people
person > person
person.first_name -> name/first
person.last_name -> name/last
person.age -> [@age]
account.person_id => person.person_id
account > person/account
account.number -> [@id]
The arrows have meanings (RHS = right-hand side; LHS = left-hand side):
- > ... Container element (no text values); RHS is the element name.
- -> ... Path to a text value; RHS is the XPath to the element name.
- => ... Join expression; RHS references the attribute in a previously listed LHS table name.
A PERSON table might resemble:
person_id | first_name | last_name | age 123 | Peter | Parker | 18 456 | James | Jameson | 42
And an ACCOUNT table might resemble:
account_id | person_id | number 1 | 123 | 123456789
Querying the database using the XPath map would produce the following XML document:
<people> <person age="18"> <name> <first>Peter</first> <last>Parker</last> </name> <account id="123456789" /> </person> <person age="42"> <name> <first>James</first> <last>Jameson</last> </name> </person>
</people>
In this case, James Jameson does not have an account and so the corresponding XML element (account) is not included in the final document.
This would make it trivial to generate a JSON document without changing the underlying code; whereas, hand-coding the XML document with combinations of the xml* functions semantically prohibits a direct transmogrification of the output format.
Thoughts?
