Token-Based Path IDs for XML Namespace Resolution
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Solution Overview
Problem
Existing database systems face inefficiencies in computing node names and namespaces for XML data, particularly when using XQuery queries, as they often require costly materialization of XML fragments or extensive computations.
Innovation Solution
The use of token-based path IDs and a token table to map tokens to namespace and name combinations, allowing for efficient computation of node names and namespaces through reverse lookups, and the creation of functional indexes for path IDs to optimize query processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional methods are used to compute node names and namespaces for XML data, then complete and accurate results are obtained, but computational costs are high and performance is poor
Solution Approach 1:
The patent pre-computes and stores path IDs for all nodes in the XML document during the indexing phase. These path IDs encode the hierarchical path information from the root to each node, including namespace and name components. When a query is executed, the system retrieves pre-computed path IDs from the XML index rather than computing them on-the-fly, significantly reducing query-time computational costs while maintaining complete and accurate node name and namespace information.
Solution Approach 2:
The patent creates a simplified copy of the XML document structure in the form of an XML index that contains path ID representations of nodes. This index is a condensed version that stores only the essential path information needed for querying, rather than storing complete XML fragments. The path IDs serve as compact representations that enable efficient lookup and computation of node names and namespaces without requiring materialization of full XML structures.
2Loss of information
If XML fragments are materialized to extract node names and namespaces, then accurate information is obtained, but storage and processing requirements increase
Solution Approach 1:
The patent extracts only the essential path information from the complete XML document structure and stores it in the XML index as path IDs. Instead of storing or materializing full XML fragments, the system extracts and stores only the hierarchical path components (namespace URIs and local names) in a condensed format. This extraction approach maintains complete node name and namespace information while dramatically reducing storage requirements compared to materializing actual XML fragments.
3Measurement precision
If extensive computations are performed to resolve node names and namespaces in XQuery, then query accuracy is maintained, but query execution time increases
Solution Approach 1:
The patent pre-computes path IDs during the indexing phase, organizing them in a structured format that enables efficient retrieval. The path IDs are pre-processed to include namespace URI and local name components in a standardized format. During query execution, the system performs simple lookup operations on these pre-computed path IDs rather than performing extensive computations to resolve node names and namespaces, maintaining accuracy while reducing execution time.
Solution Approach 2:
The patent introduces path IDs as an intermediary representation between the XML document structure and the query processing system. These path IDs serve as intermediate keys that encode path information in a compact, query-friendly format. The XQuery processor uses these intermediary path IDs to efficiently resolve node names and namespaces without performing extensive computations on the actual XML structure, thereby maintaining precision while reducing execution time.
Data Source
AI summary
In a database system, names and namespace of XML nodes are computed from path ids. The path ids are constructed from tokens, each of which represents a particular name or namespace-name pair.