I've seen the syntax for using a lookup table in a CHECK() constraint, but I cannot find a reference to it. It's not in Section 5.3.1 of the 8.2 docs. Specifically, I want to reference a table of ISO 2-letter codes for US states and Canadian provinces/territories in a table with name and address columns. Please point me to a reference. Rich -- Richard B. Shepard, Ph.D. | The Environmental Permitting Applied Ecosystem Services, Inc. | Accelerator(TM) <http://www.appl-ecosys.com> Voice: 503-667-4517 Fax: 503-667-8863