Dynamic rules are a powerful feature of Aion for defining rules to the knowledge bases at execution time. For more information about dynamic rules, see the "System Considerations for Supporting Business Rules" chapter in the User Guide. Dynamic rules differ from static rules, which are defined at edit-time and are compiled into the knowledge base executable. Dynamic rules are typically achieved by storing rules in an external medium called a rulebase. Rulebases are most commonly relational databases, such as an MS Access, a Sybase SQL Server or an Oracle database. Dynamic rules that are stored in an external medium are call persistent dynamic rules. Aion also provides support for dynamic rules that are created by logic in the knowledge base itself at execution time, see Constructing Non-Persistent Dynamic Rules.
Note: Aion provides a default rulebase in MS Access format, Rulebase.mdb, that contains no rules. This rulebase can be found in the \Rulebase subdirectory of the Aion BRE install directory. For more information about this default rulebase, see The Default and Empty Rulebases.
This section covers the runtime considerations pertaining to persistent dynamic rules, which is the most common form of dynamic rules. The principal runtime concerns regarding persistent dynamic rules center on how to load them from an external medium and post them to the inference engine. Aion also requires special consideration be given to instance binding, which, for dynamic rules, involves issues that are not found with static rules. These issues must be addressed at rule posting time. The section concludes by considering how errors that occur during dynamic rule processing (loading and posting) can be handled.
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