A method and system are provided for flexibly sectioning XML documents stored in a relational database system. The method includes obtaining a set of sectioning rules; receiving an XML document that is to be stored in the relational database system; and identifying a storage location for each node in the XML document based on the set of sectioning rules. The sectioning rules can also be used to determine which tables in the relational database should be queried when a query is received, and to determine which tables in the relational database should be updated when a command to update stored XML data is received.