Normalization and Translation of XQuery

Early approaches to XQuery processing proposed proprietary techniques to optimize and evaluate XQuery statements. In this chapter, we argue for an algebraic optimization and evaluation technique for XQuery as it allows us to benefit from experience gained with relational databases. An algebraic XQuery processing method requires a translation into an algebra representation. While many publications already exist on algebraic optimizations and evaluation techniques for XQuery, an assessment of translation techniques is required. Consequently, we give a comprehensive survey for translating XQuery into various query representations. We relate these approaches to the way normalization and translation is implemented in Natix and discuss these two steps in detail. In our experience, our translation method is a good basis for further optimizations and query evaluation.