XQuery from the Experts A Guide to the W3C XML Query Language

by Katz, Howard; Chamberlin, Don; Draper, Denise; Fernandez, Mary; Kay, Michael; Robie, Jonathan; Rys, Michael; Simeon, Jerome; Tivy, Jim; Wadler, Philip

• ISBN13: 9780321180605
• ISBN10: 0321180607
• Edition: 1st
• Format: Paperback
• Copyright: 2003-08-22
• Publisher: Addison-Wesley Professional

Summary

- Nobody knows XQuery better than this group of " experts, " after all they created it. We've cornered the market on expertise in XQuery. - Allows readers to focus on either or both a tutorial or reference-style approach as best suits them. - Currently, there are no other competing XQuery books. Authors' personal perspectives offer a welcome change to formal standards specs.

Author Biography

Howard Katz is the owner of Fatdog Software. He has more than 35 years of programming experience and is a long-time contributor of technical articles to the computer trade press, including columns on programming matters for both Microsoft and Apple Don Chamberlin, Denise Draper, Mary Fernandez, Michael Kay, Jonathan Robie, Michael Rys, Jerome Simeon, Jim Tivy, and Philip Wadler are all members of the W3C's Query Working Group, the official body defining the XQuery standard, and are prominent figures in XML- and XQuery-related industry and academic circles

Table of Contents

Preface	p. xi
Contributors	p. xix
Acknowledgments	p. xxv
Basics	p. 1
XQuery: A Guided Tour	p. 3
Sample Data: A Bibliography	p. 5
Data Model	p. 6
Literals and Comments	p. 8
Input Functions	p. 9
Locating Nodes: Path Expressions	p. 10
Creating Nodes: Element, Attribute, and Document Constructors	p. 14
Combining and Restructuring Nodes	p. 18
FLWOR Expressions	p. 18
Quantifiers	p. 36
Conditional Expressions	p. 38
Operators	p. 39
Arithmetic Operators	p. 40
Comparison Operators	p. 41
Sequence Operators	p. 46
Built-in Functions	p. 47
User-Defined Functions	p. 49
Variable Definitions	p. 51
Library Modules	p. 51
External Functions and Variables	p. 52
Types in XQuery	p. 53
Introduction to XQuery Types	p. 54
Schemas and Types	p. 56
Sequence Types	p. 60
Working with Types	p. 67
Summary	p. 77
Background	p. 79
Influences on the Design of XQuery	p. 81
The Need for an XML Query Language	p. 83
Basic Principles	p. 86
The Query Data Model	p. 89
Related Languages and Standards	p. 92
XML and Namespaces	p. 92
XML Schema	p. 95
XPath	p. 97
Other Query Languages	p. 106
Watershed Issues	p. 108
Handling of Untyped Data	p. 109
Unknown and Inapplicable Data	p. 112
What Is a Type?	p. 117
Element Constructors	p. 122
Static Typing	p. 125
Function Resolution	p. 132
Error Handling	p. 136
Ordering Operators	p. 138
Conclusion	p. 141
XQuery, XPath, and XSLT	p. 145
XSLT: A Quick Introduction	p. 145
XPath 1.0	p. 149
Why Was a New Query Language Needed?	p. 152
Differing Requirements	p. 152
Differing Cultures	p. 155
Convergence: XPath 2.0	p. 156
XSLT and XQuery Compared	p. 159
XML-Based Syntax	p. 160
Semantics of Element Construction	p. 160
Functions and Named Templates	p. 163
FLWOR Expressions	p. 164
Template Rules	p. 165
Axes	p. 166
Type Strictness	p. 168
Optimization Techniques	p. 170
Where Does the Time Go?	p. 171
Internal Coding Efficiency	p. 174
Pipelining and Lazy Evaluation	p. 175
Expression Rewriting	p. 178
Using Type Information	p. 181
Conclusion	p. 183
Formal Underpinnings	p. 185
Static Typing in XQuery	p. 187
The Benefits of Static Typing	p. 188
An XQuery Programming Scenario	p. 189
Debugging	p. 197
Validation	p. 199
Static Typing	p. 201
Getting Started with Types	p. 203
XML Schema and XQuery Types	p. 204
Values	p. 207
Sequence Types	p. 209
Schema Import	p. 210
Relating Values and Types	p. 211
Literals and Operators	p. 212
Variables	p. 214
Functions	p. 216
Conditionals	p. 218
Path Expressions	p. 219
Predicates	p. 222
FLWOR Expressions	p. 224
Element Construction	p. 226
Validation Context	p. 227
Validation Mode	p. 230
A Final Example: Grouping	p. 233
Conclusions	p. 234
Introduction to the Formal Semantics	p. 237
The Benefits of a Formal Semantics	p. 238
Getting Started with the Formal Semantics	p. 240
Dynamic Semantics	p. 241
Environments	p. 245
Matching Values and Types	p. 248
Errors	p. 250
Static Semantics	p. 254
Type Soundness	p. 258
Evaluation Order	p. 262
Normalization	p. 264
Finishing Getting Started	p. 266
Learning More about XQuery	p. 267
Values and Types	p. 267
Matching and Subtyping	p. 272
FLWOR Expressions	p. 279
Path Expressions	p. 287
Implicit Coercions and Function Calls	p. 293
Node Identity and Element Constructors	p. 298
The Forest through the Trees	p. 305
Databases	p. 307
Mapping between XML and Relational Data	p. 309
Framing the Problem	p. 310
Processing Models	p. 310
Application Types	p. 312
Sources of XML Data	p. 315
LOB or Compose?	p. 316
Composition Techniques: Common Concepts	p. 320
Generation of XML Structure through Hierarchical Joins	p. 323
Generation of XML Structure through Hierarchical Grouping	p. 324
Composition Techniques: Examples	p. 325
Default Mapping	p. 325
Extended SQL	p. 328
Annotated XML Template	p. 331
Additional Mapping Languages	p. 334
Shredding	p. 335
Creation of the Database	p. 335
Adding Extra Information to the Composition	p. 336
Inlining and Consolidation	p. 336
Support of Full XML	p. 337
Schema-Independent Representation	p. 338
Implementation Concepts	p. 339
Emitting XML Documents	p. 339
Querying and Updating XML Documents	p. 347
Conclusion	p. 350
Integrating XQuery and Relational Database Systems	p. 353
Getting Started	p. 354
Relational Storage of XML: The XML Type	p. 357
Logical Models for the XML Datatype	p. 359
Physical Models for the XML Datatype	p. 360
Encodings and Collations	p. 365
Typing an XML Datatype	p. 366
Other Aspects of the XML Datatype	p. 370
Integrating XQuery and SQL: Querying XML Datatypes	p. 370
XQuery Functionality in SQL	p. 371
Augmenting the XQuery Static Context	p. 374
Providing Access to SQL Data inside XQuery	p. 375
Adding XQuery Function Libraries	p. 378
A Note on the XQuery Data Modification Language	p. 379
Physical Mappings of XQuery	p. 380
Issues of Combining SQL, XML Datatype, and XQuery	p. 385
Top-Level XQuery	p. 386
XML Document (Fragment) Collections	p. 386
XML Views over Relational Data	p. 388
Conclusion and Issues	p. 390
A Native XML DBMS	p. 393
What Is XML Data?	p. 395
XML as Text	p. 395
XML Data Model	p. 396
Interfaces to a Native XML Database	p. 399
Interoperability	p. 400
Data-Definition Interfaces	p. 401
Update Interfaces	p. 405
Database Configuration Interfaces	p. 406
A Database Command Language	p. 411
Collections and Storage	p. 413
XQuery Client APIs	p. 414
Full-Text Search in a Native XML Database	p. 422
Sample Applications	p. 428
Invoice Archive	p. 430
A Content Management Application	p. 432
Conclusion	p. 434
References	p. 437
Glossary	p. 443
Index	p. 465
Table of Contents provided by Ingram. All Rights Reserved.

Excerpts

XML is everywhere. In an astonishingly short period of time, XML has worked itself into the nooks and crannies of corporate IT departments, academic research institutions, and small-shop programming operations everywhere. As one of the authors of this book points out, XML now encodes a bewildering array of data types scattered across a large number of diverse application domains.Where there's information, there are people who are going to need to query that information. Happily, XQuery has come along to provide a powerful and standardized way of searching through all that glorious XML-encapsulated data. Going even one better than Google, XQuery provides a flexible and easy-to-use mechanism for querying not only content, but structure as well. Taking a leaf from XSLT, XQuery doesn't content itself with simply providing a query capability; it does transformations too. I think we'll increasingly see it replacing XSLT (my own personal prediction) in a number of application areas (though XSLT aficionados needn't fearthere are plenty of things to do for both technologies). Most interestingly, some of the data that XQuery will manipulate won't even have started life as XML: a goodly portion of the data that XQuery deals and will deal with will have started life in the form of rows and columns in corporate relational databases. This BookMost technical books are either tutorials or reference works. You turn to the former if you're looking for a gentle introduction to a new subject; you look to the latter if you already know something about the subject at hand and want a minimum of hand holding while you seek out the information you need. This book is unusual in that it shares some of the characteristics of each. It's a series of technical essays and perspectives, some of them tutorial-like, on various facets of XQuery from members of the World Wide Web Consortium's (W3C) Query working group, the standards body that's been hard at work creating and crafting the formal definition of the language since the Fall of 1999. Their intimate knowledge of the matter at hand sheds a lot of light on a technical topic that some find daunting, given the weight and density of the formal spec.Members of the working group would probably be embarrassed to hear themselves referred to here as "experts," as the title implies, but that's really what they are. Nobody knows the material better than this group--after all, they're the ones who created it in the first place! This is definitely a case where you could say (pun intended) that they wrote the book. And not just the one you're holding in your hand: they also wrote most of the specification itself, since nearly every one of the authors is also a hard-working editor of one or more of the numerous documents that comprise the formal specification.The names of many of these "experts" are no doubt already known to some of you. Let me name just a few of them (to either the chagrin or the great relief of the rest of them): Don Chamberlin, a researcher at IBM's prestigious Almaden Labs, brings to bear the weighty authority he's garnered as a co-founder of SQL, a language that's played such an important role in modern technical commerce; Jonathan Robie proselytizes fiercely for XQuery and fights the good fight on the XML-DEV mailing list for the use of strong typing in XML; Michael Kay is the author of Saxon and is arguably one of the world's foremost experts on XSLT; Phil Wadler is a noted language theoretician, the principal designer of Haskell and the editor-in-chief of the "Journal of Functional Programming"; Mary Fernandez is a seasoned researcher at AT&T Labs and is well-known for her work on query languages for XML, among other research topics. Take a look at the "Contributors" section of the book to see the impressive bona fides of all our experts crew.This book provides an opportunity for these members of the working group to write individually ab