Access support tree & TextArray: A data structure for XML document storage & retrieval

The characteristics of XML documents require new ways of storing and querying such documents. Queries on both textual content and structural aspects must be supported efficiently. For this reason, we examined existing work on both document storage approaches and models for querying documents to derive requirements that are essential for the storage of XML documents. As a result of our study, we designed the Access Support Tree and TextArray (AST/TA) data structure. The important idea of the AST/TA data structure is the separation of the (logical) structure of a document from its "visible" text content. The latter is represented as a single contiguous string. At the same time the AST/TA data structure provides a tight integration to guarantee consistent changes. We introduce the AST/TA data structure formally by its abstraction, namely the AST/TA model and compare requirements of our AST/TA approach with those found in the current literature. Finally, we describe the advantage of the AST/TA model based on the AST/TA design principles.