SharePoint: Reference Data Lookup

In my SharePoint Common Reference Data Management post, I outlined several options for how to maintain and use common master data as reference data across site-collections:

• Replicated Lookup List
• Remote Lookup List
• External Database Lookup
• External Hybrid Lookup List

I've made some figures showing the four reference data designs:
Lookup metadata and content.pdf

Note that if you plan to use custom lookup columns in your site content types to get a controlled vocabulary for your taxonomy, you must test and verify that the lookup columns can:

• be used as site columns
• be filtered to show a subset of lookup values
• work in the DIP panel - fully, downgraded or not at all
• reference data in other site-collections
• be replicated across site-collections

A lookup column that can be filtered is useful as it is better positioned to support an evolving set of lookup values, e.g. hide values that become expired. Such a lookup column can be configured to work exactly as a choice column and still contain a centrally controlled vocabulary value-set.