Methods and systems are provided for separating the data of a structured document from markup structure applied to the document and for linking the separately maintained data with associated markup structure applied to the document. The data stream in an Extensible Markup Language (XML) represented document is moved outside of the document structure into a data file that is linked to the document structure. The data file and the XML-represented document structure are maintained in association with a single file (e.g., document), but in separate object models. Links are established between XML elements applied to the document and data ranges of the data file. Each of the XML structure file and the data file may be accessed and edited separately without affecting the structure or data of the other file until the two files are merged for presenting the associated document.