Excel Services

After going through the sneak preview of Share Point Server 2007, now you are somewhat familiar with Excel Services. It is likely that you have accessed web-based spreadsheets available on google or MS live sites. But have you ever thought of writing your own applications integrated with Share Point and allowing users to use these cool web-based spreadsheets? I am sure that you have thought about this at some point of time. Anyways, let’s not get into that now. :)

Excel Services are built on top of ASP.NET and SharePoint 3.0. To understand it, let us consider that there are going to be two servers: front end web serves and backend application server. The components of Excel Services are placed on these two servers. And yes, you can install all these components on one box as well.
So, what are the components installed on the front-end web server?
Excel Web Access and Excel Web Services.
Excel Web Access:
This is a simple web part, which renders Windows live spreadsheets on the requesting client’s machine. Users of this application can interact with the workbooks using this component. This web part is customizable and one can customize it based on requirements.
Excel Web Services:
Basically, you can use server-side workbook logic in your application. The programmatic approach of it, allows you to consume the web service, and do various operations. It also allows you to maintain workbook values in the session.

The application server hosts two components as: Excel Calculation Services and User Defined Functions.
Excel Calculation Services:
Its primary job is to load workbooks, do various calculations involved and execute user defined functions defined earlier. It can also cache the workbooks, the external data query results.
User Defined Functions:
I think that only one sentence given below, is sufficient to know the importance of User Defined Functions.
User Defined Functions give you the ability to use formulas in cells to call custom functions written in managed code and deployed to Microsoft Office SharePoint Server 2007. You can basically use these function to extend and customize various built-in functions or features.

Cheers,
Amol.