XML documents are containers for information. Within the primary container may be information and more containers, which themselves may contain information and more containers. These named containers form neatly hierarchical structures, creating an incr

XML documents are containers for information. Within the primary container may be information and more containers, which themselves may contain information and more containers. These named containers form neatly hierarchical structures, creating an incredibly flexible and remarkably powerful framework for storing and exchanging information of all kinds, from memos to database tables to poetry to program structures to invoices. XML documents may also include or reference sets of rules describing their structures, which applications may use to validate that documents conform to those rules.