Package – BIAN_ISO20022

This package contains diagrams that show the relationships between elements of the BIAN Metamodel and elements of the ISO 20022 Metamodel.

The BIAN Metamodel is a pure extension of the ISO20022 Metamodel that does not change the ISO20022 Metamodel. The extension is accomplished via subclassing relationships, whereby elements of the BIAN Metamodel subclass elements of the ISO20022 Metamodel. Since a subclass relationship (called a "Generalization" in UML parlance) is owned by the element playing the role of subclass, the subclassing relationships are contained within the BIAN::Level1 and BIAN::Level2 packages, and thus there are no metamodel elements that belong to this BIAN_ISO20022 package; the package contains only diagrams. The metaclasses of the ISO20022 Metamodel that appear on those diagrams are listed without documentation; the documentation can be obtained from ISO.

Comments

It is important to understand that ISO20022's RepositoryConcept element is at the top of the ISO20022 inheritance hierarchy, and thus defines properties that ISO20022 elements share in general. By making BIAN elements descendants of RepositoryConcept, BIAN elements take on those properties.

For example, BIAN elements have a name property by virtue of this inheritance, and thus BIAN elements don't contain their own name properties -- they simply use the name property that they inherit. RepositoryConcept contains many useful properties that BIAN elements need and would have to re-invent if not for their availability through this inheritance.

In general, extending the ISO20022 Metamodel provides BIAN elements with many needed properties required for a robust metamodel, and has the additional benefit of ensuring alignment with ISO20002.

Open Issue

There is an unfortunate name conflict whereby both ISO 20022 and BIAN have a BusinessArea element. We have to maintain both of these as distinct elements because we don't want to force the BIAN BusinessAreas, which can vary from bank to bank and are not canonical BIAN standards, to be the same as the ISO 20022 BusinessAreas, which have been officially defined by the governing ISO 20022 authorities. We could name the BIAN element "BIANBusinessArea" but that might be confusing since the term "Business Area" has been in heavy use in BIAN for quite some time.

In general where an element of the BIAN metamodel subclasses an ISO20022 element, such as BIANConstraint subclassing ISO20022 Constraint, we did affix a "BIAN" prefix to the BIAN element's name, in order to make the distinction between the BIAN element and its ISO20022 superclass obvious. An exception is BusinessObject, which subclasses ISO20022 BusinessComponent -- it already had a long-accepted name in BIAN that is different than its ISO 20022 superclass. However, the case of BusinessArea is different, because it is not an extension of ISO20022 BusinessArea.