1. XML Data in MS SQL Server Query and Modification Steven Blundy, Duc Duong, Abhishek Mukherji, Bartlett Shappee CS561

2. Outline Introduction XML Data Type  Structure and storage  Schema, validation  Methods Publishing  FORXML Queries

3. Approaches for XML integration to DB Mid-tier  Bi-directional XML view Query view using XPath Schema-driven approach for shredding Server-side  rowset-to-XML aggregator for XML Publishing - FOR XML  Query-driven shredding mechanism- Open XML

4. SQL SERVER 2005 XML Architecture

5. XML Storage - Native Checks Well Formedness  Validation is optional XML Documents or Fragments

6. XML Storage - DB SQL BLOB  Allows for utilization BLOB optimizations Streaming Parsing Compression  Unicode (UTF-16) Strings - UNTYPED Requires Conversion  XML Schema - TYPED Encode to match schema Much more efficient

7. XML Storage - The Numbers Advantages of Binary Storage  20 to 30% Size Reduction  Faster Limitations  2gb of stored binary per instance  Hierarchy is limited to 128 Levels

8. Storage - Schema Storage Optimization  Size  Processing Uses the XML Infoset Defined in an XMLSchemaCollection

9. Validation - Schema XML Schema Collection  Stores 1+ XML Schemas Identified by Name Space Not the Same as Constraints (No Business Logic)  Metadata Entity  Certain Type are Format Constrained i.e. Date must use ISO 8601 format Uses the XML Infoset

10. Validation - Schema Collection CREATE XML SCHEMA COLLECTION myCollection AS '<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://myBooks" elementFormDefault="qualified" targetNamespace="http://myBooks"> '

11. Validation - How? At Data Entry  Validness checked when typed data is inserted Checking Data  Applied using Cast Updated Schema  Does not Require re-validation

12. XML DT Methods All evaluate an XQuery Methods  query() - returns XML output  exists() - checks if expression results in nodes  nodes() - returns XML DT values  value() - returns value as SQL DT  modify() - modify XML data

13. query() & nodes() methods Both take XQuery string query() returns list of untyped XML nodes  Can be converted to strings  For SELECT output nodes() returns list of typed XML nodes  All XML DT methods available  count(*) works  No converting to strings

14. exist() & value() methods exist()  returns true if XQuery returns any nodes value()  Takes 2 params: an XQuery & a SQL DT  Converts xml value returned by XQuery to specified SQL type

15. Example: value() SELECT data.value(‘(/bibliograph/book/[1]/title)[1]’, ‘NVARCHAR(255)’) AS Title FROM Test Title Design Patterns

16. Example: value() w/ nodes() SELECT book.value(‘(title)[1]’, ‘NVARCHAR(255)’) AS Title FROM Test CROSS APPLY data.nodes(‘/bibliograph/book’) AS R(book) Title Design Patterns All about XML …

17. Example: exist() SELECT book.value(‘(title)[1]’, ‘NVARCHAR(255)’) AS Title FROM Test CROSS APPLY data.nodes(‘/bibliograph/book’) AS R(book) WHERE data.exist(‘/bibliograph/book’) = 1 Title Design Patterns All about XML …

18. modify() method Uses extended XQuery  insert, delete, and replace keywords Used in SQL UPDATEs

19. Example: modify() UPDATE docs SET xCol.modify(‘ insert Background after (/doc//section[@num=1])[1]')

20. Example 2: modify() UPDATE XmlCatalog SET Document.modify (' declare namespace bk = "http://myBooks"; replace value of (/bk:bookstore/bk:book [@ISBN="1-861003-11- 0"]/bk:price)[1] with 49.99')

21. XML Publishing select CustomerID as "@CustomerID", City as "address/city", PostalCode as "address/zip", ContactName as "contact/name", Phone as "contact/phone", from Customers for xml path('Customer'), root('Doc')

22. Additional Papers Used XML Support in Microsoft SQL Server 2005  Shankar Pal, Mark Fussell, and Irwin Dolobowsk  http://msdn2.microsoft.com/en-us/library/ms345117.aspx http://msdn2.microsoft.com/en-us/library/ms345117.aspx XML Best Practices for Microsoft SQL Server 2005  Shankar Pal, Vishesh Parikh, Vasili Zolotov, Leo Giakoumakis, Michael Rys  http://msdn2.microsoft.com/en- us/library/ms345115(d=printer).aspx http://msdn2.microsoft.com/en- us/library/ms345115(d=printer).aspx

23. Questions