Choosing Business Rule Providers in Heterogeneous Landscapes€¦ · NetWeaver BRM, should be...

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© 2011 SAP AG 1

Choosing Business Rule Providers

in Heterogeneous Landscapes

Applies to:

Business experts and IT professionals that are considering encapsulating business rules in either of SAP’s BRMS engines – BRFplus or SAP NetWeaver BRM - particularly where due to heterogeneous landscapes both BRMS engines are available for use. For more information, visit the Business Rules Management homepage.

A pre-requisite to apply the approaches explained in this document is:

For ABAP systems and instances - SAP NetWeaver (AS ABAP) 7.0 Enhancement Package 1 or

above.

For Java systems and instances – SAP NetWeaver (AS Java) 7.1 Enhancement Package 1 or

above.

Summary

The aim of the document is to clarify not just which of SAP’s business rules engines, BRFplus or SAP NetWeaver BRM, should be chosen as the provider of specific business rules, but also whether the native configuration of the invoking application should be used instead.

Similarly, for custom applications and enhancements to standard applications this document aids discussion on whether particular use cases should be treated as business rules at all.

Authors: Jocelyn Dart, Carsten Ziegler, Santosh Giri Govind Marthi

Company: SAP Australia

Created on: 30 November 2011

Author Bio

Jocelyn Dart is BPM/BRM Product Lead and Principal Consultant with Field Services in SAP Australia. She joined SAP in 1994. Since then she has worked with over 60 customers in a wide-range of industries in project and advisory roles. She is also well known as a co-author of the popular SAP Press book “Practical Workflow for SAP”; presenter at SAP-related conferences; and

blogger on the SAP Developer Network.

Carsten Ziegler is the Lead Architect and Chief Product Owner of Business Rule Framework plus. He joined SAP in 2000. Since then he has been working in various projects as a developer, development architect and project lead.

Santosh Giri has been part of the NW BRM team for about 5 years 6 months and has been involved in topics relating to NW BRM component like creating of customer POCs, Development of Rules Manager (Web based business user tool), Testing and also handling customers with issues on NW BRM component.

https://www.sdn.sap.com/irj/sdn/nw-rules-management


Choosing Business Rule Providers in Heterogeneous Landscapes


© 2011 SAP AG 2

Table of Contents

Purpose of this Document .................................................................................................................................. 3

Major Steps in Choose Business Rule Providers ............................................................................................... 4

What is a Business Rules Management System ................................................................................................ 4

What is SAP NetWeaver Business Rules Management (BRM) ..................................................................... 4

What is Business Rules Framework plus (BRFplus) ...................................................................................... 5

What is a Consuming Application ................................................................................................................... 5

Establish Overarching Business Rule Provider Preferences ............................................................................. 6

Major Factors in Choosing the Rule Provider for a Specific Business Rule ....................................................... 7

Rule Purpose Factors ..................................................................................................................................... 7

Business Operation Factors ............................................................................................................................ 7

Business Continuity Factors ........................................................................................................................... 7

Consuming Application Factors ...................................................................................................................... 7

Choosing the Rule Provider by Type of Rule ..................................................................................................... 9

Related Content ................................................................................................................................................ 12

Copyright........................................................................................................................................................... 13



© 2011 SAP AG 3

Purpose of this Document

This document is provided as an aid to assist business users and functional teams in identifying the correct rule provider for business rules in SAP systems, and particularly in heterogeneous landscapes that include one or more (ABAP or Java) SAP systems.

This document is not intended to be exhaustive or prescriptive, but rather to act as a guide to typical rule provider choices for common business rule scenarios and the reasoning supporting such choices.

The aim of the document is to clarify not just which of SAP’s business rules engines, BRFplus or SAP NetWeaver BRM, should be chosen as the provider of specific business rules, but also whether the native configuration of the invoking application should be used. Similarly, for custom applications and enhancements to standard applications this document aids discussion on whether particular use cases should be treated as business rules at all.

The advice given in this document has been reviewed and by relevant experts and Product Management for both BRFplus and SAP NetWeaver BRM.

This document should be read in conjunction with the article Usage Considerations – SAP NetWeaver BRM or BRFplus by Harshavardhan Jegadeesan.

This document should therefore be regarded as taking those high-level Usage Considerations to a more detailed level.

http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/19427




© 2011 SAP AG 4

Major Steps in Choose Business Rule Providers

The major steps in choosing Business Rule providers for specific business rules are:

1. Gain a high level understanding of the SAP delivered options for business rules

2. Establish overarching provider preferences for business rules

a. These are used where there is no significant advantage in establishing the rule in one

provider over another

3. Understand the major factors impacting on rule provider choices for specific business rules

4. Examine each specific business rule and choose a rule provider

a. The type of rule, the expected usage, frequency, and urgency of changes are part of this

decision.

By following these steps, business and IT professionals can be confident that the correct rule provider has been chosen, speed design of new business rules and minimize rework.

What is a Business Rules Management System

Business Rules Management Systems (BRMS) enable organizations to manage business rules for decision automation. Business users participate in and control rule definition and change; while business process experts model, validate, deploy, update, and archive business rules throughout their lifecycle. The benefit is improved decision-making, transparency and efficiency, as well as error reduction.

SAP NetWeaver offers business rules management solutions for both the Java and the ABAP stack in the form of SAP NetWeaver Business Rules Management and Business Rules Framework plus (BRFplus) respectively.

What is SAP NetWeaver Business Rules Management (BRM)

The SAP NetWeaver Business Rules Management (SAP NetWeaver BRM) component provides support for the various phases of a rules life cycle: design, execution, modification, and optimization of business rules. BRM provides the agility you needed to embed and enforce business rules in both composed business processes and standard applications.

SAP NetWeaver BRM helps you to manage the growing set of business rules in your organization via tools such as:

Rules Composer – Enables process architects and IT developers to create and modify business

rules via rule representation formats, such as decision tables. Rules composer also supports testing

and validation of business rules.

Rules Manager – Enables business users to edit and manage business rules in a Web-based

collaborative environment

Rules Engine – Executes rules, integrated with the run-time technology provided by SAP

NetWeaver Composition Environment

Rules Repository – Provides the environment for rules versioning, permissions management,

access control, alerts, and additional repository services

The integration and modification of business rules in composite business processes is supported via a native integration of the SAP NetWeaver BRM component with the SAP NetWeaver Business Process Management component. Both components leverage the same Eclipse-based development platform. This provides a single environment for designing rules and processes on the basis of consistent metadata. The result: reduced scope for error and improved productivity.

SAP NetWeaver Business Rules Management is available as an integrated capability of the SAP NetWeaver (AS Java) platform (Composition Environment).



© 2011 SAP AG 5

Additionally BRM rules can be consumed by external applications as SOAP-based web services. BRM also provides a Java API.

SAP NetWeaver Business Rules Management is available as part of SAP NetWeaver (Application Server Java) 7.1 EHP 1 and above.

What is Business Rules Framework plus (BRFplus)

BRFplus supports business analysts and IT experts with tools to find, understand, change, test and organize business rules in an integrated user interface. BRFplus facilitates seamless collaboration between business analysts and IT experts.

BRFplus perfectly integrates with SAP NetWeaver Application Server and the ABAP-based applications in the SAP Business Suite and SAP Business ByDesign. Best performance, high flexibility, and lowest total cost of ownership (TCO) are achieved by optimal integration with existing concepts and approaches are the design principles that influence BRFplus.

BRFplus is part of the SAP Basis software component, which is included in SAP NetWeaver and therefore available in all ABAP-based applications.

BRFplus consists of 3 components:

Rules Workbench – Comprises all the tools needed to manage the business rules assets in one

place through a collaborative web-based user interface. The workbench supports modeling, editing,

and managing business rules and related artifacts.

Rules Engine – Provides several ways for the invocation of rules (ABAP API, RFC, and Web

Services); can also use the fully-versioned repository to allow the user to execute the rules that were

in effect for a particular moment in time.

Rules Repository – The place where all artifacts and related information such as documentation are

saved. Artifacts can be saved as local or transportable, client-dependent or –independent. All

repository services are accessible through the workbench.

BRFplus allows business users to find the rules that matter to their business, explore and understand the rules, change and simulate/test them, and ultimately manage the rules with the BRFplus workbench. BRFplus has built-in code generation capabilities that create executable code on the fly for the highest performance. Sometimes evaluation of rules in BRFplus is even faster than a buffered single select in the database.

Rules can be deployed centrally or distributed.

BRFplus is available as part of SAP NetWeaver (Application Server ABAP) 7.01 and above.

Note: It is possible to consume a BRM rule from BRFplus using a BRMS Connector type rule or via a web service call from a Procedure Rule. Similarly BRM can consume BRFplus rules via Java Classes or XSD, although usually the invoking application would simply call the BRFplus rule as a web service in the same way that it invokes BRM rules.

What is a Consuming Application

The consuming (or invoking) application is the application that calls the business rule. Typically a consuming application also implements numerous implicit business rules as part of the native logic of the application, e.g.

Via data typing of fields used in the application;

Via application-specific configuration;

Via personalization options, etc.

Any implicit business rules which are part of the native application are effectively rules that have been pre-built and pre-consumed within the application. The cost/benefit of externalizing these pre-built rules needs to be properly considered when deciding on a rules provider.



© 2011 SAP AG 6

Usually a consuming application will also contain options to extend/enhance the application that can be used for consuming business rules from BRMS engines. Different options are likely to be available for different applications. Typical options for consuming business rules include:

Enhancement options

o E.g. Invoke rule via web service call from a Business Add-In (BaDI) or User Exit

Native integration of BRM rules

o E.g. Java applications, Embedded rules in BPM

Native integration of BRFplus rules

o In a significant number of ABAP applications

o In SAP Business Workflow (from SAP NetWeaver Application Server ABAP 7.02, e.g.

ECC6.0 EHP5)

Establish Overarching Business Rule Provider Preferences

Business Rule provider preferences may be based on a number of factors such as the preferred maintenance tool for rules, the peak volume/adaptability requirements, the relative importance of the consuming applications and whether they are deployed on the Java or ABAP instances.

The Usage Recommendations – SAP NetWeaver BRM or BRFplus provide a high level view of business scenarios appropriate to BRM versus BRFplus.

For Example:

Where the most critical business application is a composite application deployed on the Java instance, and there are very high peak volume/adaptability requirements for that application, a typical preference approach may be:

1. SAP NetWeaver BRM (Java)

2. BRFplus (ABAP)

3. Consuming application




© 2011 SAP AG 7

This would be applied as follows:

1. Where all considerations are equal, by default, business rules will be developed in SAP NetWeaver

BRM

2. Alternatively, BRFplus rules may be considered where there is a significant advantage for a

particular rule or its main consuming application (e.g. where the application has native integration to

BRFplus or the majority of data on which the rule is based is located in ABAP stack)

3. If the rule is already covered by the standard application configuration of the consuming application,

and the content of the rule does not require frequent or urgent changes, and the cost of creating and

consuming a rule external to the application exceeds the benefit, the native configuration of the

consuming application will be used as-is.

Note: There are clear benefits for simplified support and change management in standardizing to one or other rules engine as much as is practicable. Where this cannot be entirely achieved across all applications, standardizing to one or other rules engine at the application level is usually possible.

Major Factors in Choosing the Rule Provider for a Specific Business Rule

These are the major factors to be considered for most applications when determining the rule provider. Other factors may exist for specific applications.

Rule Purpose Factors

Separate decision logic (rules) and application logic – To ensure optimal performance and to minimize risk of exceptions, the rule provider should not be treated as a de-facto application, i.e.

The rule engine should not have to persist (store) data

o A rule is a synchronous call that accepts incoming parameters, performs calculations, and

returns a result to the invoking application. Storing of data is the responsibility of the invoking

application.

Business Operation Factors

Is it a true Business Operational rule? That is, is it truly a critical part of business operational decision making specific to the business and/or industry?

Does the rule have an owner? If no-one can be found to take ownership of the rule, it may not be a business rule (perhaps it is a technical rule).

Business Continuity Factors

How frequently will the rule data change?

How agile does the rule need to be? That is, to maintain business continuity what is the minimum required time between the decision to change the rule and deploying the new version of the rule?

Consuming Application Factors

How is the rule consumed? This leads to performance considerations, and considerations of native configuration options in the consuming application(s), i.e.

If an equivalent configuration option exists natively (i.e. already created and consumed) in the consuming application, the benefit of providing the rule in BRM or BRFplus should exceed the cost of creating the rule in BRM or BRFplus and then consuming it in the application.



© 2011 SAP AG 8

Note: The situation is somewhat different for native enhancement options in the consuming application, such as BADIs. In a number of scenarios, rules have been proven to perform better than writing equivalent code and the benefit of greater visibility alone can be significant. In such cases, it is advisable to consider using the native enhancement

option to consume a BRM or BRFplus rule rather than creating equivalent code directly in the enhancement.

This needs to be considered especially carefully where:

The rule is covered by the existing native functionality of the application

Changes are infrequent

Visibility requirements are low

There are no major volume or performance requirements

There is a certain amount of cost in designing the rule, creating the rule in BRM or BRFplus, and then in consuming the rule in the application. Often development costs are relatively low when the appropriate rule provider and rule type are chosen. Use of techniques such as code generation and web service generation further reduce such costs.

Note: Costs may vary depending on the options available in the specific application for consuming rules. Costs may also differ depending on which rule provider is chosen.

However where rule changes are frequent and/or rule visibility requirements are significant, benefits rapidly outweigh costs.

Lastly, in what volumes will the rule be consumed? Are there very high volumes at peak times that may affect the provider choice? Rule performance may be more efficient in BRM or BRFplus, which are designed for the specific purpose of evaluating rules, than in the native application. In such scenarios, for best performance the rule provider should be close to the data on which the rules are based (i.e. use BRM where rule data is in SAP NetWeaver AS Java instances, BRFplus where rule data is in SAP NetWeaver AS ABAP instances).

Note: Availability of skills in rules engines is not generally considered a factor, as both BRM and BRFplus are designed to be easy to learn, and a significant amount of material for this purpose is provided on the SAP Developer Network

site http://sdn.sap.com.

http://sdn.sap.com/



© 2011 SAP AG 9

Choosing the Rule Provider by Type of Rule

This table summarizes typical choices for rule providers in different scenarios based on the type (and therefore the intended usage) of the business rule. The table is not intended to be exhaustive, but rather to be an indicative guide to assist business users and functional teams in business rule design.

Flexibility and agility requirements often provide the tipping points in decisions between whether a rule should be created in a BRMS engine or not. That is, the more frequently the rule changes and/or the more urgent are rule changes (i.e. the shorter the time between the business decision to change and required deployment of the change), the greater the benefits that can be derived from implementing the rule in a BRMS engine.

Typical Flexibility/Agility Requirements is classified as follows:

None – no expectation that the rule will change over the life of the application

Low - little expectation that the rule will change, rule changes are infrequent and non-urgent

Medium – some expectation that the rule will change, rule changes may be somewhat frequent but

are not urgent

High – considerable expectation that the rule will change, rule changes are frequent and/or urgent

Type of Business Rule

Example Typical Flexibility/Agility Requirements

Provider

Data Typing Rules Date must be in valid date format

None Usually the consuming application, especially where the rule can be satisfied by a built-in data type

Mandatory/Optional Rules

E.g. Field X on Form Y is required

Low to Medium Would changing the rule require a static change to the consuming application as well? If yes, the rule provider is the consuming application.

Are dynamic changes to mandatory/optional settings permitted by the application? If yes, then BRM or BRFplus may be appropriate if justified by the frequency of change.

Are there any localization requirements? E.g. different areas have different mandatory/optional requirements for the same form. If so, BRM or BRFplus may be appropriate.

Commonsense Validation Rules

From Date must be less than To Date

None Consuming application (native part of application – will never change)

Simple Validation against Master Data E.g. simple dropdown lists, Simple duplicate checks (id must be unique)

Account must be valid on the chart of accounts, New account id must be unique

None Consuming application (native part of application – cost of implementing in BRM or BRFplus typically exceeds benefit)



© 2011 SAP AG 10



Provider

Complex validation against Master Data e.g. Complex duplicate checks

There is already a third party relationship with the same appropriated agency, drawing agency, appropriation type, appropriation item, outcome, program, valid for year and agreement type

Medium May justify BRM/BRFplus rule if likely to change from time to time, or check is complex and not covered by standard application configuration

Security Access Rules

User cannot activate measure unless they have the “unlock measure” permission

None to Medium Depends on frequency of change/visibility requirements:

Use security of consuming application if change infrequent and low visibility requirements

Otherwise use BRM or BRFplus

User Interface operation rules

When user clicks on checkbox x, fields y and z are displayed/hidden

None to Medium Depends on frequency of change/visibility requirements:

Part of the consuming user interface if change infrequent and low visibility requirements

Otherwise use BRM or BRFplus

Business Operation Validation Rules - Simple

Date must be in future valid Pay Period

None to Low (rules may change – but change not likely)

May be covered by the consuming application

Business Operation Validation Rules - Complex

Date must be between pay period + 1 but also in the same financial year, unless pay period is the last of the financial year...

Medium to High (Historically has this changed from time to time? How often? What would suggest frequency of change)

Usually BRM (Java) or BRFplus (ABAP)

Technical note: RETE rules preferred when using BRM

Calculation Rules Formulas, e.g. rate calculation such as x = y * (z + ab ) / 100

Low to High Usually BRM (Java) or BRFplus (ABAP)

Technical note: Flow rules preferred when using BRM

Decision Rules If a=b, choose path c Medium to High BRM (Java) or BRFplus (ABAP)

Agent Determination Rules

Find recipient of work item, choose recipients of email notification

Medium to High Unless very simple and covered by the application configuration or a simple user group/security role (effectively a simple distribution list), use BRM (Java) or BRFplus (ABAP)



© 2011 SAP AG 11



Provider

Recommendation Rules

Discrepancy identified – field x is greater than field y (as input to human decision)

Low to High BRM (Java) or BRFplus (ABAP)

Personalization Rules

Only show certain columns to a specific user, Standard sort order is by field xyz

Low to Medium Usually consuming application (native part of application –cost of implementing in BRM or BRFplus typically exceeds benefit)

Internationalization and Localization Rules

Rules that differ depending on localization requirements such as agency, affiliate, country, etc.

Medium to High BRM (Java) or BRFplus (ABAP) Note: To satisfy access requirements separate rulesets may be needed for different localization groups

Exceptions and Special Rules

Rules that trigger alerts

Medium BRM (Java) or BRFplus (ABAP)

Optimization and Configuration Rules

Rules built into the application logic

Low to High Likely to be consuming application (use native capabilities), unless very high volume in which case BRM or BRFplus may provide improved performance handling

Human Rule Extremely complex, partly subjective decision, e.g. may need consideration of impact on specific personnel, industrial agreements, legal agreements, political or commercial implications, etc.

Medium to High Do not (entirely) systemize – leave as part of a human decision.

However BRM or BRFplus rules may be used to assist in the decision-making by:

a) Using rules to identify the decision maker

b) Using rules to provide a recommended decision, which the decision maker accepts/overrides.

By using rules the number of cases where human intervention is required can be minimized, the time-to-decision reduced, and the opportunity to automate maximized.



© 2011 SAP AG 12

Related Content

Usage Recommendations - SAP NetWeaver BRM or BRFplus

Business Rules Management with SAP: BRFplus and SAP NetWeaver BRM

BRFplus Performance and Sizing

SAP NetWeaver Business Rules Management Best Practices

For more information, visit the Business Rules Management homepage.

https://www.sdn.sap.com/irj/sdn/index

http://www.sdn.sap.com/irj/sdn/nw-rules-management?rid=/library/uuid/109becc1-c6ba-2e10-7ead-ed5c052ed217

http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/a03e423b-fb6b-2d10-3a8c-86a17ba6cccf

http://www.sdn.sap.com/irj/sdn/nw-rules-management?rid=/library/uuid/f0c2010e-49ca-2e10-1eab-f64fab153deb




© 2011 SAP AG 13

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Choosing Business Rule Providers in Heterogeneous Landscapes€¦ · NetWeaver BRM, should be...

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