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Frank Richards wrote: > XML is a tree of elements. Naively mapping that tree onto a table causes the > RDBMS to > thrash it's guts out doing joins to go down the tree -- [ ... ] > XML in an > RDBMS can easily hit six or seven joins per query. A typical, naive definition of a "nodes" table does lead to unacceptable performance due to the necessity of many self-joins. It is possible, however, to devise a scheme for encoding nodes' context in a compact form, optimized for an RDBMS' indexing facility, and build a generic table structure, capable of storing any well-formed XML, yet does not exhibit the self-join problem. With this technique, one can: * leverage the mature ACID properties of commercial RDBMSs * support any well formed XML with no additional developer or DBA effort * provide fine-grained, random access to the content of large collections * efficiently query on content and/or structure Bill Lindsey B-Bop
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