I hope you all have been enjoying Zeyad's articles showing some of the powerful solutions you can build leveraging the Open XML API. Thanks for pulling these all together Zeyad, and I look forward to seeing some of the other solutions we've talked about.
Today, there is a new post from Eric White that you should all go take a look at: http://blogs.msdn.com/ericwhite/archive/2008/11/14/using-linq-to-query-excel-tables.aspx#comments
Eric pulled together a neat prototype where he allows folks to write LINQ queries against tables within a Spreadsheet. Rather than writing the query against the basic constructs of the file format which the SDK already allows, you can actually leverage the semantics of the table, so for a table of inventory you can essentially write queries that say "give me the total quantity of all bicycles ordered." It leverages the Open XML API, so it can run server side without the need for Excel. It's just a prototype and we could definitely add more functionality, but it's an awesome proof of concept!
I've talked with a number of developers over the past year and seen the excitement folks have around LINQ and the ease with which you could query various data sources. I have a ton of spreadsheets that have tables of data, and I thought it would be great if I could query one of those tables in the same way I'd query a SQL table. So Eric and I talked about it a bit, and he decided to pull together a proof of concept. Very cool Eric!