The Query Data Model

The first step in designing XQuery was to specify the data model on which the language operates. The Query data model [XQ-DM] represents XML data in the form of nodes and values, which serve as the operands and results of the XQuery operators. XQuery is closed under the Query data model, which means that the result of any valid XQuery expression can be represented in this model. Since all the operators and expressions of XQuery are defined in terms of the Query data model, understanding this model is the key to understanding the language.

In defining the Query data model, the working group did not intend to deviate from existing standards, but to conform to them wherever possible. Therefore, the Query data model draws from ...

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