Business intelligence with Excel Services 2013 - Business Intelligence in Microsoft SharePoint 2013 - page 183

UdFs
UDFs are simply managed code assemblies written to perform a specific task, which are deployed to
the server. These managed assemblies can be called from a workbook just like any other Excel func-
tion. So, they can take a set of parameters from other cells in the workbook and return a single value
or an array of values.
UDFs are particularly useful if there are custom, coded, routines you are using to calculate a
particular set of values in a particular way. They are also great mechanisms to perform other tasks in
the system or in another system. Some examples I have seen of how UDFs have been used include
refreshing data from a SharePoint list, writing some custom data values specific to the user view-
ing the workbook into a data store, retrieving values from a custom data store, performing complex
mathematical computations, or parsing data from the web and returning a list of values based on the
custom web query.
UDFs aren't a replacement for full Visual Basic for Applications (VBA) solutions or macros; they
don't provide any type of object model against a workbook on the server.
More Info To learn more about UDFs go to http://msdn.microsoft.com/en-us/library/
ms493934.aspx .
excel Web Services
Excel Services provides a SOAP-based web service that allows programmatic access to workbook files
loaded on the server. The web service isn't only for use on the “web.” You can call it from any applica-
tion that knows how to call a web service including custom-built client-side applications and other
Microsoft applications such as InfoPath.
The web service is a great way to access values from a workbook for cases in which you don't
need the Excel UI. With it, you can do things such as set values, recalculate the topic, refresh the
data, and retrieve the entire workbook or values from certain cells. If the Office Web Applications are
installed and Excel Services editing capabilities are enabled, it also allows you to persist values in the
workbook.
More Info To learn more about Excel Web Services, go to http://msdn.microsoft.com/
en-us/library/ms572330.aspx .
eCMAScript (JavaScript, JScript) object model
The Excel Services ECMAScript object model is similar to the web services in many ways. It facilitates
loading of workbooks, setting values, recalculating and refreshing them, and the ability to retrieve
values from the workbook. It also supports a number of things that the web service doesn't, such as
displaying the UI and an event model.