A data store is provided for storing, relating and for allowing use of data associated with a computer-generated document. Data for structuring information associated with a document, such as document metadata, is maintained in the data store where relationships between different pieces of data are maintained in a location distinct from the surface level view of a document. The data store exposes interfaces to the various pieces of data in the data store for allowing different applications to access and operate on one or more of the data pieces. The pieces of data may be structured according to a markup language such as the Extensible Markup Language (XML), and XML schemas may be associated with each piece of data for allowing the data store to validate the structure applied to the data based on an XML schema associated with a given piece of data.