Coding Schemes

FPML concept which we make use of extensively. It is defined as:

A number of data elements defined in FpML are restricted to holding one of a limited set of possible values, e.g. currency, business calendar locations, etc. Such restricted sets of values are frequently referred to as domains.In FpML, two different codings of domains are used. Domains that are small and not expected to change during the life of the specification are coded using XML schema enumerations. These domains are described elsewhere, in particular in the fpml-enum schema file. Other domains are coded using a strategy that has been defined by the Architecture Working Group, referred to as 'Schemes'. Each Scheme is associated with a URI. Coding Schemes can be categorized as one of the following:

• An external coding Scheme, which has a well-known URI. In this case the URI is assigned by an external body, and may or may not have its own versioning, date syntax and semantics. The external body may be an open standards organization, or it may be a market participant. It's worth stating that a scheme provides alternate identifiers for one identity. However it is not used to identify things other than the identity of the thing that contains it.
• An external coding Scheme, which does not have a well-known URI. In this case FpML assigns a URI as a proxy to refer to the concept of the external Scheme, but this URI will not be versioned or dated
• An FpML-defined coding Scheme. In this case the Scheme is fully under FpML control and the URI will change reflecting newer versions and revisions as the scheme evolves and changes.