CIS-764

1
CIS-764 Database Design

• Service-Oriented Architecture
• and Web-Services
• Binti Sepaha

2
Overview

• Introduction
• Definitions/Concepts
• Steps in Building a Web-Service
• Web-Service by Example
• Benefits of Web-Services
• Conclusion
• References

3
Introduction

• History of Software Development
• Modular Approach
• Code reuse - sub-routines and functions
• Maintenance became a problem
• Object-Oriented Programming
• Reuse code but not functionality
• Component-based Software Development
• Reuse functionality
• components were written in different
  languages
• Changes became tough, redistribution was
  tough

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Service-Oriented Architecture Web-Services

• Greater Reuse
• Web Interface
• Loose Coupling enables business flexibility
• Use the best service provided by service
  providers based on the consumers criteria
• Platform-independence
• Integration of several services
• Application Integration became easier

5
Definitions/Concepts

• Service
• A service is a function that is well-defined,
  self-contained, and does not depend on the
  context or state of other services. Services are
  long running executables.
• Web-Service
• A Web-Service is a piece of software that makes
  itself available over the Internet and uses a
  standardized XML messaging system.
• Service Provider
• A company that provides a service by exposing it
  through a dynamic discovery service.

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Definitions/Concepts (contd.)

• Service Consumer
• A program that consumes or subscribes to a
  service provided by a service provider.
• Dynamic Discovery
• An intermediary between providers and consumers.
  
• Universal Description, Discovery and Integration
  (UDDI) is a directory service where businesses
  can register and search for Web services.
• Message
• Communication means between service providers
  and consumers.

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Definitions/Concepts (contd.)

• WSDL (Web-Services Description Language)
• WSDL provides a way for service providers to
  describe the basic format of web service requests
  over different protocols. WSDL is used to
  describe what a web service can do, where it
  resides, and how to invoke it. 
• SOAP (Simple Object Access Protocol)
• SOAP is a protocol specification that defines a
  uniform way of passing XML-encoded data. In also
  defines a way to perform remote procedure calls
  (RPCs) using HTTP as the underlying communication
  protocol. SOAP essentially provides the envelope
  for sending the Web Services messages.

8
Steps in Building a Web-Service
9
Steps in Building a Web-Service (contd.)

• Discovery
• through dynamic discovery (UDDI)
• Description
• through WSDL
• Packaging
• through SOAP (XML)
• Transport
• through HTTP
• Network
• through Internet or local intranet (TCP/IP)

10
Web-Service by Example
11
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Benefits of Web-Services

• More reuse
• Better Scalability
• Service Assembly
• Higher Availability
• Code Mobility (location transparency)
• And many more

13
Conclusion

• Developers must switch to Service-Oriented
  Architecture

14
References

• www.ondotnet.com
• www.service-architecture.com
• www.msdn.com
• www.webservices.xml.com
• www.capeclear.com
• www.developer.com