After studying this chapter you will be able to: Identify how databases and spreadsheets are both similar and different; list and describe the four steps in designing and building a relational database; define the concepts of entity class, instance, primary key, and foreign key; given a small operating environment, build an entity-relationship (E-R) diagram. | Lecture 24 Enterprise Systems Development ( CSC447) COMSATS Islamabad Muhammad Usman, Assistant Professor College of Statistical and Acturial Science Service Orientation © SE;Service orientation, Hans van Vliet Overview Services, service description, service communication Service-Oriented Architecture (SOA) Web services SOSE: Service-Oriented Software Engineering Italian restaurant analogy Restaurant provides food: a service After the order is taken, food is produced, served, : service may consist of other services The menu indicates the service provided: a service description The order is written down, or yelled at, the cook: services communicate through messages © SE;Service orientation, Hans van Vliet Main ingredients Services Service descriptions Messages Implementation: through web services Other example Citizen looking for a house: Check personal data System X Check tax history System Y Check credit history System Z Search rental agencies System A,B © SE;Service orientation, Hans van Vliet What’s a service Platform-independent computational entity that can be used in a platform-independent way Callable entities or application functionalities accessed via exchange of messages Component capable of performing a task Often just used in connection with something else: SOA, Web services, © SE;Service orientation, Hans van Vliet What’s a service, cnt’d Shift from producing software to using software You need not host the software Or keep track of versions, releases Need not make sure it evolves Etc Software is “somewhere”, deployed on as-needed basis SaaS: Software as a Service © SE;Service orientation, Hans van Vliet Key aspects Services can be discovered Services can be composed to form larger services Services adhere to a service contract Services are loosely coupled Services are stateless Services are autonomous Services hide their logic Services are reusable Services use open standards Services | Lecture 24 Enterprise Systems Development ( CSC447) COMSATS Islamabad Muhammad Usman, Assistant Professor College of Statistical and Acturial Science Service Orientation © SE;Service orientation, Hans van Vliet Overview Services, service description, service communication Service-Oriented Architecture (SOA) Web services SOSE: Service-Oriented Software Engineering Italian restaurant analogy Restaurant provides food: a service After the order is taken, food is produced, served, : service may consist of other services The menu indicates the service provided: a service description The order is written down, or yelled at, the cook: services communicate through messages © SE;Service orientation, Hans van Vliet Main ingredients Services Service descriptions Messages Implementation: through web services Other example Citizen looking for a house: Check personal data System X Check tax history System Y Check credit history System Z Search rental agencies .
