Native XML Sequence Handling in SQL Systems
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Solution Overview
Problem
Current relational database management systems (RDBMSs) lack effective support for XML sequence type and XQuery sequence, leading to inefficient handling and potential loss of information when converting between XMLType(sequence) type instances and other XML types, as existing SQL functions are not designed to operate correctly with XMLType(sequence) type instances.
Innovation Solution
Development of SQL functions such as PKSQL2XML, UPKXML2SQL, XQRNG, SEQ2CON, CON2SEQ, XQCONCAT, XQAGG, XQSEQUENCE, XQEXTRACT, and XQEXTRACTVAL to handle XML sequences correctly, along with rules to simplify abstract syntax trees (ASTs) representing SQL queries, enabling efficient evaluation and conversion between XMLType(sequence), XMLType(content), and XMLType(document) types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If existing SQL functions are used to handle XML sequences, then the system can process XML data, but information is lost and processing is inefficient because the functions are not designed for XMLType(sequence) type instances
Solution Approach 1:
The patent introduces new SQL functions specifically designed for XMLType(sequence) type instances, changing the functional parameters from generic XML handling to sequence-specific operations. This enables correct semantic handling of XML sequences while maintaining processing efficiency through native function support.
2Adaptability or versatility
If XML sequences are converted to other XML types using existing functions, then conversion is possible, but the conversion is inefficient and may lose information
Solution Approach 1:
The patent introduces conversion functions (SEQ2CON, CON2SEQ) as intermediaries that specifically handle XML sequence type conversions. These intermediary functions preserve the semantic meaning and information integrity during type conversions between XMLType(sequence), XMLType(content), and XMLType(document).
3Productivity
If existing SQL query processors are used, then queries can be executed, but XML sequences are not handled effectively requiring additional processing overhead
Solution Approach 1:
The patent extends the functionality of existing SQL query processors to natively handle XML sequences by introducing a comprehensive set of SQL functions that work seamlessly with XMLType(sequence). This multi-functional approach allows the query processor to handle both traditional relational data and XML sequences uniformly, improving ease of operation without sacrificing processing speed.
4Productivity
If XML sequences are supported natively in SQL systems, then processing becomes more efficient, but the system complexity increases
Solution Approach 1:
The patent segments the XML handling functionality into distinct SQL functions for different operations (creation, conversion, extraction, aggregation). This segmentation allows the SQL system to support XML sequences natively through modular, specialized functions rather than requiring a complete system redesign, thus managing complexity while improving efficiency.
Data Source
AI summary
Techniques for effectively and efficiently supporting XML sequence type and XQuery sequence natively in a SQL system are described. According to one aspect, SQL functions that correctly handle XML sequences are provided. Thus, XML sequences are handled effectively. According to another aspect, rules for simplifying an abstract syntax tree (AST) that represents one or more such SQL functions are provided. For each such SQL function that is represented in an AST that represents a SQL query, one or more rules that are relevant to that SQL function are determined. Relevant rules are applied to the representation of the SQL function within the AST. Through the application of the rules to the representations of the SQL functions within the AST, the AST is modified in a manner that simplifies the AST prior to the evaluation of the AST at query execution time. Thus, XML sequences are handled efficiently.