Microsoft Rule Engine Survey

June 1, 2010

Are you interested in helping to shape Microsoft’s future rules products?

Microsoft is running a survey on rule engines in general, and its own rule products (WF Rules, MS BRE) in particular through the end of this week – June 4. (I would have blogged it yesterday, but was off due to holiday.)

The survey should take approximately 5 minutes to complete. If you have used the WF Rules product, you will get a few additional questions about your usage of the features. If you only use non-Microsoft rule engines, your participation is welcome as well.

Your input is appreciated.

Microsoft Rule Engine survey

Rules In WF4

March 17, 2010

My blog stats show trending topics around searches for “wf4 rule engine” and “wf rule engine” and “wf rules” among other variations. If those topics are leading people to this blog, then I might as well address the topic directly.

What Is WF?
For those who don’t know what the queries above mean – it means that people are searching for the rule engine feature (named Windows Workflow Foundation Rules Engine aka “WF Rules”) in Microsoft’s Windows Workflow Foundation (aka WF). The feature originally shipped with .NET 3.0, and I have written previously about the feature set especially as it compares to Microsoft’s other rules offering.

Changes To WF
With .NET 4.0, the Workflow Foundation is introducing a new workflow model (more details here) – so we now talk about the workflow model in .NET 3.0/3.5 as “WF3” and the new workflow model in .NET 4.0 as “WF4”. However, as mentioned at that link, all of WF3 is still available in .NET 4.0. (Note: the assemblies ship in the ‘Extended’ .NET 4.0 install and not the ‘Client’ .NET 4.0 install.)

Rules Integrated With WF4
WF4 does not include a new forward chaining rules engine that is closely integrated with the WF4 activity model (that does not preclude one being made available in the future). Again, to be very clear, the existing WF Rules features are still available in .NET 4.0 and may be used within WF4. Put another way, there is still a forward chaining rules engine in .NET – it has not gone away. A direct statement from Microsoft on the topic can be seen on the .NET Endpoint blog as follows:

“Two other major WF 4 activities that were discussed at PDC, a new state machine activity and a new forward chaining ruleset activity, will not be available with the VS2010 beta 1 release – and we will cover each of these topics in greater depth in the next month. At this point, a new forward chaining rules engine won’t be ready for the .NET 4 timeframe, and will probably see a CTP release post-VS2010 to gather feedback and to allow customers the opportunity to evaluate the direction we are considering. It’s important to note that we are working to ensure integration with the WF 3 rules engine will be possible in a number of ways, though; one example of integration back to the WF 3 rules engine is the SDK sample activity I mentioned above.”

WF3 -> WF4 Migration
There is also now some rules-specific migration guidance published here as part of some overall WF3->WF4 migration guidance. See also the WF Migration Kit CTP 1 that I posted about previously. Questions about using the WF3 rules with WF4 should most likely be addressed via the forums.

Tell Microsoft What Rules Features You Would Like To See For .NET
Finally, if you have interest in rules on the .NET platform and are willing to provide feedback to Microsoft – I encourage you to do so. In fact, it would be great if you could be as concrete as possible about your feature needs. The inclusion of a feature often depends on customer feedback. Here are some examples of feedback that you could provide to Microsoft:

  • If using the existing WF Rules feature with WF4 via the Interop activity satisfies your technical needs and why or why not.

  • If you would like to see WF Rules more fully integrated with the WF4 programming model, or not.

  • If you use or would like to use rules in applications apart from WF.

  • Specific feature feedback about WF and/or MS BRE.

  • If your needs skew more towards the runtime rule engine or BRMS tools.

Specific feature requests for the future should be provided through Connect (detailed instructions for providing feedback about WF4 through Connect).
Also, if you are interested in discussing your rules scenarios and requirements in more detail with someone from Microsoft, you can contact me via the contact form on this blog, or email me at my firstname.lastname at my employer’s

Microsoft’s Rule Engines

February 5, 2010

I am often asked to describe the rule engines that Microsoft ships. (The first question being: “Microsoft has rule engines?”) This question frequently comes from folks who know rules, but don’t know .NET. This post is specifically written to answer the question. Should the offerings change in the future, I will update this post as needed.

As always, this is not an official Microsoft statement. Questions about the future directions for these products should be directed to Microsoft.

As of this writing, Microsoft is currently shipping two rule engines. They are aimed at somewhat different audiences as described below.

The first rule engine is called the Microsoft Business Rule Engine (sometimes called “MS BRE” or “BRE”) and it has shipped as part of BizTalk Server since early 2004. BRE has shipped in BizTalk Server 2004, BizTalk Server 2006, BizTalk Server 2006 R2, BizTalk Server 2009 and I’m sure it will be included in the upcoming BizTalk Server 2009 R2.

WF Rules
The second rule engine is part of Windows Workflow Foundation in .NET, it is the Windows Workflow Foundation Rules Engine (sometimes called “Workflow Rules” or “WF Rules”). The WF rule engine originally shipped in late 2006 as part of .NET 3.0. It was also included in .NET 3.5 and .NET 4.0. If you are running Windows 7, Windows Server 2008 R2, Windows Server 2008, or Windows Vista or have installed .NET 3.0 or higher – you already have the WF rule engine on your computer. Update: I have an additional post specifically about rules in WF4.

Comparing MS BRE & WF Rules
Here are some comparisons of these engines written by other folks. Charles Young has written extensively on this topic.

A Short Summary Of Differences For Those Who Know Rules
If you asked me to summarize differences for a rules specialist, my comments would be along the following lines:

  • MS BRE is part of a BizTalk Server, which is a business-oriented server package, while WF Rules is part of the free .NET Framework which is more developer-oriented. (MS BRE may be used standalone outside of BizTalk, but is only licensed with BizTalk.) Both engines provide forward chaining execution. WF Rules also provides the option for sequential execution.
  • MS BRE rules are typically authored in the Rules Composer, while WF Rules are typically authored in Visual Studio. There are partners that provide a more BRMS-like authoring environment. MS BRE has features such as vocabularies and a respository, and is therefore closer to what Gartner defines as a BRMS.
  • MS BRE implements the Rete algorithm, while WF Rules does not. MS BRE uses eager evaluation, while WF Rules uses lazy evaluation. The performance profiles are accordingly different – WF “first hit” execution being faster, for example.
  • WF does not have assert/retract keywords or a Working Memory, while MS BRE does – so WF Rules requires all objects to be reachable from a common root object (this). (In WF Rules, support for multiple instances is achieved through forward chaining.) WF Rules supports “Else”, while MS BRE does not. MS BRE has some known restrictions around negation-as-failure. MS BRE has special handling for XML and DB fact types.

Related Technology
I would be remiss if I did not mention some Microsoft offerings that apply to related areas:

Lastly, I should also point out that the Mono Project is reimplementing Windows Workflow Foundation – including WF Rules.