Union and Lists

posted by  kevyn (54)  13 months ago (blogs.msdn.com)

Last time we talked about built-in simple types and how additional types can be defined as restrictions of those types. Now, we will talk about the remaining kinds of simple types: unions and lists.

According to the W3C spec, list types are data types where the legal values are finite-length sequence of values. Each list type can be a list of a specific itemType. Within SQL Server 2005, we do not permit the creation of list of lists, list of union types and list of xs:ID. List types can be derived from the built-in atomic types, user defined restricted atomic types or anonymous