Accessing BLOB Data from External Systems Using Business Connectivity Services in SharePoint Server 2010
Tajeshwar Singh wrote a white paper which shows you how to use Microsoft Business Connectivity Services (BCS) in Microsoft SharePoint Server 2010 to access and surface BLOB data in the SharePoint user interface and search. Check out the overview below taken from the paper.
Overview of the white paper
Microsoft Business Connectivity Services (BCS) is the new version of Microsoft Office SharePoint Server 2007 Business Data Catalog functionality. New features are added that help retrieve binary large object data (referred to as BLOB data) from external systems and make it available in Microsoft SharePoint Server 2010. This article describes the following:
- The functionality that is provided by the StreamAccessor stereotype that is introduced in Business Connectivity Services.
- How to use StreamAccessor to retrieve file attachments from external systems for viewing and indexing.
- How to write the BDC model that is required to consume BLOB data.
- The built-in Web Parts behavior for BLOB data, and how BLOB fields can be indexed by SharePoint Server search.
In this article's scenario, the AdventureWorks database that is hosted in Microsoft SQL Server 2008 is used as an external system that contains the binary data. The BDC metadata model is created with a StreamAccessorMethodInstance to retrieve the BLOB field of type varbinary from SQL Server as an external content type. The BLOB fields are modeled as types that can be read in chunks to help Business Connectivity Services read the stream in chunks, and not load the complete content in memory. This can help prevent out-of-memory conditions. An example of such a type is System.IO.Stream in the Microsoft .NET Framework. An External Data Grid Web Part is configured to show the external items with links to download the BLOB. Finally, Search is configured to crawl the BLOBs and show the results in the SharePoint Server search user interface (UI).
- Lionel Robinson, Program Manager