Structural Properties of XPath Fragments
ICDT '03 Proceedings of the 9th International Conference on Database Theory
The complexity of XPath query evaluation
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Theoretical Computer Science - Database theory
Deciding well-definedness of XQuery fragments
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On the complexity of nonrecursive XQuery and functional query languages on complex values
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
ACM SIGMOD Record
From XQuery to relational logics
ACM Transactions on Database Systems (TODS)
On the expressive power of XQuery-based update languages
XSym'06 Proceedings of the 4th international conference on Database and XML Technologies
Highly expressive query languages for unordered data trees
Proceedings of the 15th International Conference on Database Theory
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XQuery is known to be a powerful XML query language with many bells and whistles. For many common queries we do not need all the expressive power of XQuery. We investigate the effect of omitting certain features of XQuery on the expressive power of the language. We start from a simple base fragment which can be extended by several optional features being aggregation functions such as count and sum, sequence generation, node construction, position information in for loops, and recursion. In this way we obtain 64 different XQuery fragments which can be divided into 17 different equivalence classes such that two fragments can express the same functions iff they are in the same equivalence class. Moreover, we investigate the relationships between these equivalence classes.