What is a Proxy Code List?
Each external code table has a proxy schema whose only purpose is to add the metadata attributes on the SuperType so that they can be used with the properties that use those code values. The "base" contains the code values and the "base proxy" hooks (or adds) the SuperType metadata to the code (enumerated) elements. jxdm.xsd imports the base proxy (and adds the SuperType metadata) and the base proxy imports the base (and adds the values).
Here is an example that illustrates the concept of proxy schema. Suppose we want to specify the color of a person's eyes using the NCIC code for eye colors. The XML would look like
It would have been easier if we could have directly added the metadata reference to the external type rather than creating a proxy type, but we are not the owners of the external types and namespaces and cannot change their data to suit our needs.