BizTalk Developer Interview Questions and Answers - Business Rule Engine

Introduction

This article intends to cover the answers to BRE related questions, which a BizTalk developer can face at during an interview.

Questions and Answers

What is Business Rules Engine?
A run-time inference engine that can link highly readable, declarative, semantically rich rules to any business objects (.NET components), XML documents, or database tables. It can evaluate rules against facts and initiate actions based on the results of that evaluation.
What is the tool that I need to use to create Business Rules?
You need to use the Business Rules Composer. This is a graphic tool used for authoring, versioning, and deploying policies and vocabularies.
What is Business Rule Language?
It is a rule markup language in XML format for declarative rule definitions.
How can I execute a Business Rule in my orchestration?
Using the Call Rules Shape. See more here.
What is used to create new vocabulary definition?
Vocabulary Definition Wizard is used to create vocabulary definitions.
What is a Policy?
A policy is a logical grouping of rules. You compose a version of a policy, save it, test it by applying it to facts, and, when you are satisfied with the results, publish it and deploy it to a production environment. See more here.
Is it possible to change Business Rule policy after it was published?
No. After policies are published it can't be edited.But if there is a need to have change in policy then new version of policy is to be created.
Does rule composer have provision of adding ELSE logic?
No, there is no provision of adding ELSE but else logic can implemented with extra IF.
What is Long term fact and Short Term fact?
Fact is the user data to which rule conditions are applied. At design time a fact is a reference to that data.
Facts have two categories – Short Term Facts and Long Term Facts. Consider a loaning process of any Bank. We can think a “loan application” as short term fact. Short team facts are business information which changes per occurrence. On the contrary, “interest rates” do not change very regularly. This business information is steady and we can consider it a long term fact. See more here.
What is the difference between Publishing and Deploying the Rule ?
Rule alone cannot be published or deployed , it has to be wrapped under Policy and then published and deployed. When policy is deployed it is ready to use and can't be edited whereas when published, policy aren't ready for use .
Can we call policies from .Net code?
Yes. Firstly it needs to be declared (policy name which is to be called), passed in the fact instance and finally executed.
Can we call specific version of Policy using Call rule shape in Orchestration?
No, as the call rules shape calls the latest version of the policy deployed.
What is purpose of BizTalkRuleEngineDb?
This database is a repository for:
Policies, which are sets of related rules
Vocabularies, which are collections of user-friendly, domain-specific names for data references in rules.
Is there limit for versions of policies ?
No.
What is Rete Algorithm, does it have any relation with BRE?
Rete Algorithm is an efficient pattern matching algorithm for implementing production rule systems. BRE's inner working is based on Rete algorithm.
How does it differ, calling policy in Call Rules Shape and in Expression ?
The Call Rules shape in the Orchestration calls only the latest version of the policy. To call an older (specific) version from within an orchestration, the Business Rules Framework APIs is used, which can be called from within an expression.