XPath Navigation Limits SQL/XML Databases (Part 9)
TechNotes Logic in DB Beyond Java Data Access SOX SQL/XML Restructuring Trees Open Source BizIntel MySQL Drivers ODBC JDBC OLE DB .NET Podcast SQL:2003 MS SQL 2005 XML DBs XQuery Webcast XQuery SQL:2003 MS SQL 2005		<<Prev 1 2 3 4 5 6 7 8 9 In Example 3, the two LCA nodes involved in this nonlinear hierarchical query are indicated. They are determined by the WHERE clause qualification which is located only in the Invoice node in this example. The qualified Invoice node occurrences qualify the other related node occurrences. For example, the Addr node is qualified by the Invoice node occurrence through the Cust node occurrence because it is the Lowest Common Ancestor that makes the connection. On the other hand, the Dpnd node is connected to Invoice through the Emp node occurrence because it is the LCA in this case.   Fast, reliable data access for ODBC, JDBC, ADO.NET and XML This demonstrates the nested LCA coordination logic between different legs of the structure for nonlinear hierarchical processing, and can get very complicated in its processing. It is automatically performed in the ANSI SQL engine. This SQL level hierarchical processing is fully described in our ANSI SQL hierarchical processing tutorial at http://www.adatinc.com/images/Hierarchical_Structures_and_4GLs.pdf.   The above nonprocedural navigation-less standard SQL query is specified easily and processed automatically. It is too complicated to be realistically performed by procedural navigation. In addition, even linear queries performed by nonlinear processing are performed more: easily, quickly, consistently, and accurately than today’s procedural navigation processing of hierarchical structures. This functioning beta product proves this next generation hierarchical processing technology is possible and is now available again today. To see other actual more advanced examples of the ANSI SQL native XML hierarchical processing capabilities described here, see our SQLfX® user guide at http://www.adatinc.com/images/Verifying_SQLfX_Current.pdf. About the Author Michael M David is founder of Advanced Data Access Technologies, Inc. Previously a staff scientist and the lead XML architect for NCR/Teradata and their representative to the ANSI SQLX Group. Before the advent of relational databases, he designed and implemented commercial hierarchical query languages and program generator products for Informatics General and Sterling Software. He has over twenty-five years experience researching and designing commercial non-procedural, heterogeneous relational and hierarchical database processing products. Based on this experience, he has authored the book Advanced ANSI SQL Data Modeling and Structure Processing and many papers and articles on this subject. His company has developed the first ANSI SQL Transparent XML Hierarchical Processor. Contact Mike at mike@adatinc.com.   << Prev 1 2 3 4 5 6 7 8 9 Database Server Watch  SQL Summit Home Page    Articles    © 2008, Ken North Computing LLC, All rights reserved.