Database adapter - should be used for Oracle Apps schema?

Hi,
I have a requirement of pulling all the records from Oracle Apps for Purchase Order transactions happened during some period. Can anybody tell me where can I find guidelines for using Database Adapter or Oracle Apps adapter for pulling all the Purchase order records from Apps schema.
I think Database Adapter is not a right choice for the pulling data from Oracle Apps schema, as the shchema structure in Apps is complex and the tables are linked as well.

So, if I have to use Oracle Apps Adapter - then what should I use - APIs, Tables/Views, XML Gateway..

Please help.

Thanks.