Summary: Learn about the options available for using the Secure Store Service with Excel Services to refresh data from external data sources.
This series of articles describes how to configure data refresh in Excel Services in SharePoint Server 2013 by using the Secure Store Service to map user and group credentials to the credentials of external data sources.
In Secure Store you specify a group of users to whom you want to grant access to a data source and a set of credentials that has access to that data source. The user information is stored in a Secure Store target application and the associated credentials are stored, encrypted, in the Secure Store database. You can then specify the target application in a workbook, an Office Data Connection (ODC) file, or in Excel Services Global Settings, and Excel Services will use the stored credentials on behalf of the specified users to refresh data in a data-connected workbook.
External Data Connections: You can specify a Secure Store target application in an Office Data Connection (ODC) file and then connect to that ODC file in Excel. When you publish the workbook to a SharePoint document library, it maintains its connection to the ODC file. The connection information in the ODC file is used when Excel Services refreshes the data in the workbook. Using an ODC file has the following advantages:
A single ODC file can be referenced by multiple workbooks. If the data source connection parameters change (for example, if you want to use a different Secure Store target application than the one originally specified) you need only update the ODC file and not the workbooks themselves.
Using ODC files allows administrators to create and maintain the data connections that are used by the organization. You can create data connections appropriate for users, place them in a trusted data connection library, and then notify the users of which ODC files to use for their queries.