SBVR_ — Authorizations & Support for "Dark World" Assumptions

ISSUE NAME: Authorizations & Support for "Dark World" Assumptions PROBLEM: The current approach in SBVR is based on a "light world" assumption (everything permitted unless expressly prohibited). As has been pointed out by Mark Linehan and others, there are cases where the opposite assumption ("dark world") is appropriate (everything is prohibited unless expressly permitted), especially for authoization. PROPOSED RESOLUTION: SBVR already has the support necessary for 'dark world' assumptions; it simply needs to be explained and illustrated. I propose the following text be inserted into SBVR at the appropriate point, perhaps in 12.1. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (PROPOSED TEXT TO BE INSERTED) Authorizations SBVR makes a ‘light world’(1) assumption about rules. In a ‘light world’, anything that is not expressly prohibited is assumed permitted. Business rule practice indicates that this choice is the appropriate one for the large majority of business problems. Occasionally, practitioners may discover cases in which the opposite assumption is appropriate. In such ‘dark world’ circumstances, anything not expressly permitted is assumed prohibited. Such cases might involve use of, and/or access to, resources that are deemed especially sensitive, dangerous, scarce, and/or valuable. For that reason, it makes sense to grant permission for use and/or access explicitly. Such permissions are often called “authorizations”. SBVR does not offer any specialized support for authorizations. None is needed. Support for authorizations is accomplished as follows: * A rule is expressed to declare that some general area of business activity is prohibited except where expressly permitted (i.e., ‘dark’). * Specific advices of permission, qualified as appropriate, are given to indicate selective authorizations. The following examples illustrate. Example 1. Fact type: person makes payment ‘Dark’ Rule Statement: A person may make a payment only if making the payment is expressly permitted for the person. Advice of Permission Statements: * A senior manager may make a payment. Note: This rule statement could also be expressed: A person may make a payment if the person is a senior manager. * Jane Smith may make a payment. Note: This rule statement could also be expressed: A person may make a payment if the person is “Jane Smith”. Example 2. Fact type: ice road is used by vehicle ‘Dark’ Rule Statement: An ice road may be used by a vehicle only if using the ice road is expressly permitted. Advice of Permission Statements: * An ice road may be used by a vehicle if the ice road is north of the arctic circle. * The ice road with the name, Yukon 12,000 Foot Lake Road, may be used by a vehicle. * An ice road may be used by a vehicle if the average temperature at the southern-most point has been below 0o C for at least 5 days. 1 (footnote) Ronald G. Ross, "The Light World vs. the Dark World ~ Business Rules for Authorization," Business Rules Journal, Vol. 5, No. 8 (August 2004), URL: http://www.BRCommunity.com/a2004/b201.html

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