AIXM Business Rules
Why necessary
The AIXM UML model defines, using UML class diagrams, the information items that are in the scope of the "aeronautical information" domain. This includes definitions of classes, attributes and relationships between classes. For attributes, constraints expressed as lists of values, range of values, pattern are also included in the AIXM UML model. The AIXM XML schema is derived from the UML model and defines elements that correspond to the AIXM model classes, attributes and association role names. The values of XML elements and data types derived from UML attributes are constrained based on the data types defined in the UML model - list of values, data ranges and/or patterns.
More complex constraints, such as dependencies between the values of different attributes (sometimes in different classes), detection of 'out of range' values, mandatory properties for class of objects, etc. are not included in the AIXM UML model and do not appear in the XML Schema. Thus, there is need to document such more complex constraints as "business rules". The aim of providing AIXM Business Rules is to be able to define what is possible or allowed in an AIXM data set, in particular with regard to data values.
Not all the AIXM Business Rules are equally applicable in all communities of AIXM users. The most obvious example are mandatory properties for AIXM features - in a flight planning community, there is no need to include in an AIXM data set the frequency/channel of a navigation aid. On the other side, such attributes are mandatory for data sets provided to an air navigation community. Therefore, the aim of the AIXM Business Rules is to document an exhaustive pool of rules, from which profiles for a particular community can be extracted. This includes requirements for minimal data properties, data quality and any other operational constraints, such as the rules for frequency pairing for VHF navaid, etc. This also includes structural rules that are specific to the AIXM context (such as the relation between the type of TimeSlice and its validity period, etc.) and which are not enforceable with the AIXM XML schema.
An AIXM Business Rules Profile was defined for the data input to the European AIS Database (EAD). Additional profiles are being defined for the ICAO digital data sets (AIP, obstacles, etc.) and for Digital NOTAM.
Rules grammar - two versions
Current version - applicable since 2024
The objective of the "new SBVR syntax" is to maximise the potential for automatic generation of data set validation code from the AIXM Business Rules. This is achieved through the following changes in the AIXM Business Rules approach:
a strict AIXM business rules grammar
use of the AIXM XML elements and attributes as vocabulary (SBVR noun-concepts) instead of the classes/properties/associations from the UML model;
This new approach is documented here: Version 2 (starting in 2024)
Previous version - until 2023
The initial approach for the AIXM 5.x business rules was based on SBVR as rule language and on the AIXM UML model as business vocabulary. This was applied for the provision of the AIXM Business Rules for the European AIS Database (EAD), until end 2023. This approach is documented here: Version 1 (until 2023)
