The term business rule or English Business Rule referred to in the industry computer science as a collective term different types of rules that are used in or in connection with computer programs. It is not necessarily understood to be a business matter, but business rules can also describe very elementary technical issues.
A simple example from the telecommunications sector:
WENN das Telefonat länger als 30 Minuten gedauert hat UND das Telefonat zwischen 18:00 Uhr und 24:00 Uhr geführt wurde UND der Tarif des Besitzers Student 30+ heißt DANN wende 10 % Rabatt auf das geführte Telefonat an.
A decision table can also be used to define many similar rules . Such rules form the basis for rule-based systems , which in the broader sense can be assigned to the special field of artificial intelligence (AI). In the past, these were often based on the idea that emerged with the Prolog programming language of finding the solution to a problem by systematically trying out possible combinations of if-then rules or by mathematical inference. Newer AI methods in this direction use, among other things, artificial neural networks and fuzzy logic . However, these typically offer only limited traceability, if at all. Based on business process management for the modeling of process flows or, even more finely, based on model-driven software development , methods for the graphic modeling of rules are also available today. These are particularly suitable for graphically illustrating complex rules and their cross-references.
In many cases, however, business rules are also understood to mean something much simpler, namely specifications that describe how a computer program or business process that is controlled by a computer program should behave. For example, a plausibility rule , usually in the form of a formula, describes when data entered into application software are valid. These data are only allowed to be saved if all applicable plausibility rules are met. There are also calculation, visibility, authorization and many other types of rules that describe the target behavior of a program or process.
Business rules are often written down by the specialist department of a company as a specification for software developers in the specification and then have to be manually and laboriously incorporated into the computer programs. Business rule management systems , or BRMS for short, offer the option of managing these rules separately in a business rule repository , all the more transparency (for the department), flexibility (in the event of changes to the business rules) and cost savings (through shorter development and change cycles of the computer program). The execution of the rules from the repository is then controlled by a business rule engine . These systems are usually written in the programming languages C ++ or Java .
The aim of a BRMS is to isolate the rules from the data access, process and presentation layers of a computer program from the outset and to make them available at a central point at any time for new requirements and other programs.