Ideal for complex apps with frequently changing rules, BRMSes (business rules management systems) give businesspeople and programmers a shared language that helps them implement changes quickly. Two companies, Fair Isaac and ILOG, make enterprise-class rules management systems for Java applications. Both recently announced they are bringing their premier products to .Net apps, and I've had a chance to see ILOG's new Rules for .Net in action.

ILOG's solution combines a rules engine that runs on .Net, a shared rules repository accessible via Windows SharePoint Services, and sets of plug-ins for Visual Studio .Net and Microsoft's Word. Programmers create rules in Visual Studio, export them as XML-based "RuleDocs," and business analysts edit them using Word. Giving businesspeople the ability to maintain rules in Word (using ILOG's English-like Business Action Language) is a big step forward, far preferable to using ILOG's own GUI or spreadsheet-like Decision Tables. ILOG says plug-ins for Excel and the ability to create rules for BizTalk Server are on the road map.

For developers, Rules for .Net provides total access to rules, objects, and classes from Visual Studio .Net. As in JRules, developers can add virtual classes to extend the object model quickly and easily. Rules are contained in Visual Studio and Microsoft Word documents, but Rules for .Net provides the same debugging capabilities as ILOG's JRules and Rules for C/C++. The product supports a document-centric rules management process, but it lacks a true rules repository as found in JRules and Fair Isaac's Blaze Advisor. Nevertheless, Rules for .Net could be a clear winner for Microsoft shops needing a first-class BRMS.