Friday, March 02, 2007

Recent ADO.NET 3.0 Entity Framework Posts

The ADO.NET Team blog has two new posts about the Entity Framework:

Publish an RSS Feed from a Relational Table

Tim Mallalieu's RSS Feeds with ADO.NET Entity Framework and the ASP.NET RSS Toolkit post describes how to create an RSS feed from the Northwind Products table, the Entity Framework, and the new ASP.NET RSS Toolkit from the ASP.NET Sandbox catalog. Here's the toolkit's description:

The RSS toolkit includes support for consuming as well as publishing RSS feeds in ASP.NET applications. Features include:

  • RSS Data Source control to consume feeds in ASP.NET applications
    • Works with ASP.NET data bound controls
    • Implements schema to generate columns at design time
    • Supports auto-generation of columns at runtime (via ICustomTypeDescriptor implementation)
  • Caching of downloaded feeds both in-memory and on-disk (persisted across process restarts)
  • Generation of strongly typed classes for RSS feeds (including strongly typed channel, items, image, handler) based on a RSS URL (the toolkit recognizes RSS and RDF feeds) or a file containing RSS definition. Allows programmatically download (and create) RSS channels using strongly-typed classes. The toolkit includes:
    • Stand-alone command line RSS compiler
    • Build provider for .rssdl file (containing the list of feed URLs)
    • Build provider for .rss file (containing RSS XML)
  • Support for generation of RSS feeds in ASP.NET application including:
    • RSS HTTP handler (strongly typed HTTP handlers are generated automatically by the build providers) to generate the feed.
    • RSS Hyper Link control (that can point to RSS HTTP handler) to create RSS links
    • Optional secure encoding of user name into query string to allow generation of personalized feeds
  • Set of classes for programmatic consumption and generation of RSS feed in a late-bound way, without using strongly types generated classes

My September 4, 2006 Generate RSS Feeds with ASP.NET and LINQ to XML post describes a simple approach to creating feeds from arbitrary data sources, such as event logs.

Note: Julie Lerman wrote an article for ASP.NET Pro magazine about the toolkit and control adapters: Playing in the ASP.NET Sandbox.

Learn More about Entity Framework's Object Services

Brian Dawson, an ADO.NET Program Manager, offers a brief description of EF's Object Services layer in his Object Services – Write less code post. Brian covers the following topics with objects materialzed from the Entity Data Model:

  • Queries with Entity SQL (eSQL)
  • Queries with LINQ
  • CRUD operations on the Northwind Products table
  • Creating and resolving concurrency conflicts

Forum Discussion on Entity Framework Update Performance

Danny Simmons answers David Hubbard's questions about update performance with a discussion of the EF's ObjectStateTracker and change tracking in this "Questions about performance" thread in the the ADO.NET Orcas forum.

Entity Framework vs. LINQ Mystery Paper

Julie Lerman mentioned a recent ADO.NET Team post that "addresses one of the biggest questions about querying against the Entity Framework - what are the pros & cons of Entity SQL vs. LINQ" that's disappeared. She says, "In discussing this, the post also lays out a lot of great background info."

This reminds me of the original missing ADO.NET vNext white papers fiasco in mid-May 2006, as described in my ADO.NET 3.0 Entity Framework Ephemera post.

Keep an eye on the ADO.NET Team blog for the return of the "Entity Framework vs. LINQ Mystery Paper."

While you're waiting for the "Mystery Paper," check out Kevin Hoffman's August 2006 LINQ to Entities vs. LINQ to SQL - What should I use and when? post (be sure to read the comments.) Steve Eichert believes LINQ to Entities is the better choice under any set of conditions. C# MVP John Papa's LINQ 101 - Which Flavor? posts adds his distinction between LINQ to Entities and LINQ to SQL.