Using XML with Legacy Business Applications

Patterns for Identifiers

Identifiers are all around us. Social Security numbers, zip codes, and DUNS numbers (unique numbers issued by Dun & Bradstreet and used to identify business entities) are just a few. The range of values of such things is usually way too large and dynamic to practically enumerate in a schema, although business applications usually validate them in their databases. Even though we might not want to enumerate the set of allowable values, we can do a level of validation by specifying a pattern to which the identifier must conform. For example, U.S. Social Security numbers have the general pattern NNN-NN-NNNN, where N represents a digit from 0 through 9. U.S. zip codes (in the five-digit form) have a pattern of NNNNN. The common ...