Office 12 And XML

For those who are interested, you can download some Word files that contain more information about the XML file format that will be used in Office 12.

When you save a document, it will actually be a bunch of files in a zip archive. If it's an Excel document, the file will have an extension of *.xlsx or *.xlsm (if it contains macros).

Developers can now determine if any code exists within an "Office 12" document before opening it. Previously this "advance notice" wasn't something that could be easily accomplished outside of Office. A developer can inspect the package file for the existence of any code-based parts and relationships without running Office and potentially risky code. If a file looks suspicious, a developer can remove any parts capable of executing code from the file, so the code can cause no harm.

Here's something else about Excel:

In order to optimize loading and saving performance and file size, "Excel 12" stores only one copy of repetitive text within the Excel file. In order to do so, "Excel 12" implements a shared string table in a document part called [strings.xml]. Each unique text value found within a workbook is listed once in this part. Individual worksheet cells then reference the string table to derive their values.

So while this process optimizes Excel's XML file format, it also introduces some interesting opportunities for additional content manipulation solutions. Developers in a multinational organization could leverage the shared string table to offer a level of multilanguage support. Instead of building unique workbooks for each language supported, a single workbook could utilize string tables that correspond to different languages. Another possibility would be to use string tables to search for keyword terms inside a collection of workbooks. Processing a single, text-only XML document of strings is faster and simpler than having to manipulate the Excel object model over many worksheets and workbooks.

This is an excerpt regarding Excel's ability to integrate live data:

... the manager will be able to take advantage of a new feature of the Open XML Formats, which allows external applications to place streams of XML data within the file. Instead of cutting and pasting, the manager will embed a data stream from the sales tracking system within the forecast spreadsheet. When the manager opens the document in Excel for "Office 12," the stream will load and the data in the spreadsheet will be updated dynamically.

My understanding is that free updates will be available for Office 2000, 2002, and 2003. The updates will allow these versions to read/write the new file format.

It will be interesting to see how well this actually works. Office 2003 had the first stab at XML file formats, and it left a lot to be desired. Can Microsoft pull it off on the second try?

Additional reading: Brian Jones's Office XML Formats blog.