State of the Art in Web Services

1
State of the Art in Web Services Commercial
Databases

• Outline
• Web Services Technologies
• JDBC
• XML, SVG, PNG
• XMLP, SOAP, WSDL, UDDI
• Commercial Databases
• IBM DB2
• Oracle 9i
• Microsoft SQL 2000
• Information Integration
• Access to web data sources

2
Data Management for GIS

• Database Implementation (e.g. IBM GFIS)

GIS Information
How dose it look? (graphical data)
Where is it? (coordinates)
What is it? (attribute data)
Spatial Database
3
Why use database for spatial data?

• Better data management for spatial data. Users
  gain access to full function spatial information
  systems based on industry standards with an open
  interface to their data (e.g. SQL).
• Spatial data is now stored in enterprise-wide
  database, thereby facilitating spatially enabling
  many more application.
• Reduced complexity of systems management by
  eliminating the hybrid or file based
  architectures of traditional GIS-based data
  management schemes.

4
JDBC (Java Database Connectivity)

• Why use JDBC?
• Establish a connection with a database or access
  any tabular data source.
• Send SQL statements.
• Process the results.

5
JDBC Architecture

• The JDBC API contains two major sets of
  interfaces the first is the JDBC API for
  application writers, and the second is the
  lower-level JDBC driver API for driver writers.
  JDBC technology drivers fit into one of four
  categories. Applications and applets can access
  databases via the JDBC API using pure Java JDBC
  technology-based drivers, ODBC drivers, and
  existing database client libraries as shown in
  the following figures

6
XML (eXtensible Markup Language)

• DTD (Document Type Definition)
• A DTD defines a class of XML documents using a
  language that is essentially a context-free
  grammar with several restrictions.
• RDF (Resource Description Framework)
• It provides a general method to describe metadata
  for XML documents
• It describes resources, which are objects
  identified using Uniform Resource Identifier
  (URIs)
• XSL (eXtensible Stylesheet Language)
• It is a language for transforming and formatting
  XML

7
XML (cont.)

• XPath
• XPath defines the syntax and semantics of
  path expressions such as the following, which
  matches the last report child (in document order)
  of the weather descendants of the node with
  unique identifier favorites id("favorites")/des
  cendantweather/childreportposition()last()
• XPointer
• The XML Pointer Language (XPointer)
  extends XPath to support applications by adding
  two new axes to specify basis steps in XPath.

8
Querying XML Data

• Requirements for a query language for XML
• Precise Semantics An XML query language should
  have a formal semantics.
• Rewritability, Optimizability XML data will
  often be generated automatically from other
  formats relational, object-oriented,
  special-purpose formats.
• XML Output An XML query should yield XML output.
• Compositional Semantics Expressions in the XML
  query language should have referential
  transparency.
• No Schema Required An XML query language should
  be usable on XML data when there is no schema
  (DTD) known in advance.

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An example XML-QL

• Selection and Extraction Selection in XML-QL is
  done with patterns and conditions. The example
  below selects all books published by
  Addison-Wesley after 1991
• WHERE ltbibgt ltbook yearygt
  ltpublishergtltnamegtAddison- Wesleylt/namegtlt/publisher
  gt
• 
  lttitlegt t lt/titlegt
• 
  ltauthorgt a lt/authorgt
• lt/bookgt lt/bibgt IN
  "www.a.b.c/bib.xml", y gt 1991
• CONSTRUCT a
• Reduction and Restructuring The following query
  retrieves the same data as above but groups the
  results differently
• WHERE ltbibgt ltbook yearygt
  ltpublishergt ltnamegtAddison-Wesley lt/gt lt/gt
• 
  lttitlegt t lt/gt
• 
  ltauthorgt a lt/gt
• lt/gt lt/gt IN
  "www.a.b.c/bib.xml", y gt 1991
• CONSTRUCT ltresultgt ltauthorgt a lt/gt
• 
  lttitlegt t lt/gt
• lt/gt

10
Web Services
The World Wide Web is more and more used for
application to application communication. The
programmatic interfaces made available are
referred to as Web services.
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Web Services (cont.)

• A Web Service a service accessible via XML
  messages over Internet protocols.
• SOAP Simple Object Access ProtocolA lightweight
  protocol to exchange information in a distributed
  environment based on XML.
• WSDL Web Services Description LanguageA
  language to describe the functions provided by a
  web service.
• UDDI Universal Description, Discovery and
  IntegrationA meta service to locate web
  services - www.uddi.org.

12
SVG (Scalable Vector Graphics)

• Whats SVG?
• SVG is a language for describing two-dimensional
  graphics in XML.
• Types of graphic objects
• Vector graphic shapes, images, and text.
• Its relationship with our project
• We can use SVG to describe the graphs in civil
  engineering XML documents.

13
PNG (Portable Network Graphics)

• Whats PNG?
• An extensible file format for the loss less,
  portable, well-compressed storage of raster
  images.
• Its relationship with our project
• We can use it to store the images of boreholes
  and other related geotechnical data in our
  documents.

14
IBM DB2 Universal Database

• Platform
• Windows NT, 2000, IBM AIX
• Embedding ESRI
• IBM's collaborative relationship with ESRI, which
  includes embedding ESRI technology within DB2
  Spatial Extender,
• is one of its GIS solutions.
• IBM DB2 Spatial Extender
• DB2 Spatial Extender manages the updating,
  structuring and insertion of geospatial data and
  enables development of the spatial database
  schema.

15
San Francisco maps city services with IBM DB2 and
DB2 Spatial Extender
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Oracle 9i DatabaseSpatial

• Oracle Spatial
• Address-based data
• Customer Lists
• Locations of Assets
• Map data
• Roads
• Parcels
• Remotely Sensed data
• Satellite Imagery
• GPS
• Aerial Photography

17
Oracle 9i Database (cont.)
Oracle9i applies spatial indexes to any data in
relational databases. Oracle Locator includes
R-tree indexing, in addition to quadtree indexing
capability. R-tree indexes can be used in place
of quadtree indexes, or in conjunction with them.
In addition, R-tree indexing can be used for any
3D and 4D indexing of data critical to solving
problems in oil exploration, architecture,
engineering, and many other scientific
application.
Queries can be spatially constrained, as defined
by an "area of interest" chosen by the user.
Eliminating data outside the area of interest
from consideration during queries ensures optimum
performance levels.
18
Microsoft SQL Server 2000

• Geographic data MapPoint works against any ODBC
  compliant data source, including MS Excel, MS
  Access, and MS SQL Server 2000.
• Ease of use A simple user interface (UI) and
  straightforward documentation help ensure that
  everyone in your organization can use MapPoint.
  Users can be productive quickly, without the
  downtime or cost typically associated with
  training them in new business intelligence tools.
• Integration with Office As part of the Office
• product family, MapPoint is
  well-integrated
• with the other Office applications. This
  gives
• MapPoint a strong advantage over
  competing
• products with regard to users personal
• productivity.

19
Information Integration
Research by Craig Knoblock Cyrus Shahabi Steve
Benton José Luis Ambite USC/Information Sciences
Institute
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Information IntegrationSingle Interface to
Multiple Sources
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MotivationTheaterLoc Entertainment Agent
Hollywood.com Trailers
Tiger Map Server
Etak Geocoder
Agent
Zagat
CuisineNet
Yahoo Movies
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TheaterLoc
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Information Integration

• The problem of providing
• uniform (sources transparent to user)
• access to (query, and eventually updates too)
• multiple (even 2 is a problem!)
• autonomous (not affect the behavior of sources)
• heterogeneous (different data models, schemas)
• structured (at least semistructured)
• data sources (not only databases)

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Principal Dimensions of Information Integration

• Virtual vs. materialized architecture
• Access query only or query update?
• Mediated schema
• Mediated schema requires schema integration and
  then query reformulation. Two main approaches
• Global as View
• Local as View
• Language for descriptions and queries
  conjunctive queries (CQs), union of CQs, Datalog
  (recursion), first-order logic (?,?,?),
  description logics
• Types of Sources
• Structured (DBs) vs. semi-structured (Web)
• Source capabilities positive and negative

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Materialized Architecture Data Warehouse
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Virtual ArchitectureMediator
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Mediator Architecture

• User queries in global (mediator) schema
• Mediator translates and decomposes user query
  into multiple source queries

28
Wrapper Building Tools

• Wrappers provide uniform query language for data
  access
• Wrapping Web-pages by Non-experts
• Demonstration-oriented user interface enables
  users to show system what to extract by example
• System automatically induces extraction patterns
• Simplifies wrapper maintenance

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Example of Extraction Rule
Muslea et al 1999
RULE sequence of landmarks (e.g., Cuisine )
Page
ltbgtNamelt/bgtChinois on Mainltbgt Cuisine ltpgt
lt/bgt Pacific New Wave ltbrgt
Start SkipTo(Cuisine ) SkipTo(lt/bgt)
End SkipTo(ltbrgt)
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Example of Rule Induction
Muslea et al 1999
Training Examples
ltpgtCuisineltpgtltbgtThailt/bgtltpgtReviewltpgt ltbgt
Good ltpgtReviewltpgtltbrgtltpgt ltbgt Excellent
SkipTo(
ltbgt ) SkipTo(ltpgt ltbgt) ... SkipTo( )
SkipTo(ltbgt) ... SkipTo(ltpgt)SkipTo(ltbgt)
SkipTo(Review ) SkipTo( ltbgt )
...
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Matching Objects Across Sources

• Problem how to decide that objects in two
  sources refer to the same object in the real
  world
• Example Zagat Fodors
  CPK California Pizza Kitchen
  Ralphs Ralphs Grill
• Information Retrieval techniques for similarity
  joins Cohen,SIGMOD-98 TejadaKnoblock