体系结构和流程设计的应用

陈士昂整理 日期：05 年10月17日知识素材：体系结构和流程设计的应用2022-7-17AMT企业资源管理研究中心 本资料在企业资源管理研究中心（AMT）文档控制范围之内，在得到许可后方可使用资料来源：资料来源：Application Architecture&Process Design知识素材知识素材日日 程程第一部分 何谓信息系统的体系结构第二部分 集中式和分布式的体系结构第三部分 信息系统设计中的数据库设计第四部分 用户和数据系统界面问题第五部分 大标题5第六部分 大标题63Application Architecture&Process DesignIntroduction:The chapter will address the following questions:What is an information systems architecture in terms of DATA,PROCESSES,INTERFACES,and NETWORKS the building blocks of all information systems?What are both centralized and distributed computing alternatives for information system design,including various client/server and Internet/intranet options?What are the database and data distribution alternatives for information system design?What are the make versus buy alternatives and variations for information system design?What are the user and system interface alternatives for information system design?4Application Architecture&Process DesignIntroduction:The chapter will address the following questions:What are the various networking topologies and their importance in information system design?What are the methods for general application architecture and design?What are the differences between logical and physical data flow diagrams,and explain how physical data flow diagrams are used to model application architecture and guide process design?How do you draw physical data flow diagrams for a system/application?5Application Architecture&Process DesignGeneral System Design:During general systems design the basic technical decisions are made.These decisions include:Will the system use centralized or distributed?Will the systems data stores be centralized or distributed?If distributed,how so?What data storage technology(s)will be used?Will software be purchased,built in-house,or both?For programs to be written,what technology(s)will be used?How will users interface with the system?How will data be input?How will outputs be generated?How will the system interface to other,existing systems?6Application Architecture&Process DesignGeneral System Design:The decisions made during general systems design constitute the application architecture of the system.An application architecture defines the technologies to be used by(and to build)one,more,or all information systems in terms of its data,process,interface,and network components.It serves as a framework for general design.7Application Architecture&Process DesignINFORMATION SYSTEMS FRAMEWORKSYSTEMANALYSTSINFORMATION TECHNOLOGY ARCHITECTURESYSTEMBUILDERS(components)SYSTEMDESIGNERS(specification)SYSTEMUSERS(requirements)SYSTEMOWNERS(scope)DatabaseArchitectureDatabase ScehmaData RequirementsBusiness SubjectsFOCUS ONSYSTEMDATAApplication SchemaBusiness ProcessesBusiness FunctionsFOCUS ONSYSTEMPROCESSESInterface SchemaInterface RequirementsSystem ContextFOCUS ON SYSTEMINTERFACESProcessor and Software ArchitectureInterfaceArchitectureNetworkingArchitectureNetwork SchemaCommunication Reqts.Operating LocationsFOCUS ONSYSTEMGEOGRAPHYArchitecture ProjectorConfiguration Implementation Phase(deliver the new system into operation)Design/Construction Phases(design and develop the system solution)Definition Phase(establish and prioritize business system requirements)Study Phase(establish system improvement objectives)Survey Phase(establish scopeand project plan)System DevelopmentCUSTOMER customer-no customer-name customer-rating balance-duePRODUCT product-no product-name unit-of-measure unit-price quantity-availableORDER order-no order-date products-ordered quantities-orderedOrder FormHelp+Customer FormProduct LookupLogonNew CustomerNew OrderOrder AcceptedChange of AddressFirst OrderRequest Order HelpOrder Help CompleteRequest Product LookupRequest Product Lookup HelpProduct Lookup Help CompleteCustomers order zero,one,or more products.Products may be ordered by zero,one,or more customers.MarketingAdvertisingOrdersSalesCancellationsServicesOrder Management SystemCustomerAccounts Receivable DatabaseWarehouseBankOrderPicking OrderCreditCredit VoucherCheck creditValidate customerValidate productsRelease orderCustomersOrdersProductsorder customer numbervalid order order without valid customercredit order with valid productsapproved order quantity in stock approved orderrejected order prices picking ticket EDI CustSt.Louis HQLA OfficeIndy Ware-houseNY OfficeWest CustomersEast CustomersMaintenance RecordsProducts Catalogordercatalog changesship ordership ordership ordercreditcreditserviceCUSTOMER customer_no Alpha(10)INDEX customer_name Alpha(32)customer_rating Alpha(1)INDEX balance_due Real(5,2)PRODUCT product_no Alpha(10)INDEX product_name Alpha(32)unit_of_measure Alpha(2)unit_price Real(3,2)quantity_available Integer(4)ORDER order_no Alpha(12)INDEX order_date Date(mmddyyyy)CUSTOMER.customer_noORDER_PRODUCT ORDER.order_no PRODUCT.product_no quantity_ordered Integer(2)Order Processing ProgramProcess an OrderInitiation RoutineShutdown RoutineGet an OrderValidate an OrderFile an OrderCheck Customer CreditCheck Product DataCheck Credit DataRelease an OrderCustomersProductsOrdersSt.Louis MainframeIndy AIX ServerNT Server LANT Server NYCommunications ControllerPBXEnternet LAN AIX/Lan ManagerEthernet LAN/NTEthernet LAN/NTClient PCClient PCClient PCClient PCFirecracker SalesDatabase DecisionsProcess DecisionsInterface DecisionsNetwork Decisions8Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing What is client/server computing?8A client is single-user computer that provides(1)user interface services,appropriate database and processing services;and(2)connectivity services to servers(and possibly other clients).8A server is a multiple-user computer that provides(1)shared database,processing,and interface services;and(2)connectivity to clients and other servers.8In client/server computing an information systems database,software,and interfaces are distributed across a network of clients and servers which communicate and cooperate to achieve system objectives.Despite the distribution of computing resources,each system user perceives that a single computer(their own client PC)is doing all the work.9Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server ComputingClient/server computing is an alternative to traditional centralized computing.8In centralized computing,a multi-user computer(usually a mainframe or minicomputer)hosts all of the information system components including(1)the data storage(files and databases),(2)the business logic(software and programs),(3)the user interfaces(input and output),and(4(any system interfaces(networking to other computers and systems).The user may interact with this host computer via a terminal(or,today,a PC emulating a terminal),but all of work is actually done on the host computer.10Application Architecture&Process DesignWhat is the client and operating system?Where are user/system interface instructions executed?Where is the business logic instructions executed?Where are database commands executed?The clients are either dumb(non-programmable)terminals,or PCs(any OS)that are emulating dumb terminals using software.Any system interfaces are either executed on the server or across the network on another server.The user interface(usually non-graphical)is stored and executed on the server.All business logic is programmed to execute on the server.Resulting data files may be transferred to another server across the network.All data is stored on the server and all file and database access and update commands and instructions are executed on the server computer.CentralizedComputingThe clients are personal computers or workstations(sometimes called fat clients)running Windows 9x,Windows NT,OS/2,or Macintosh OS.Any system interfaces are either executed on the server or across the network on another server.All business logic is programmed to execute on the server.Resulting data files may be transferred to another server across the network.All data is stored on the server and all file and database access and update commands and instructions are executed on the server computer.Distributed Presentation ComputingThe clients are personal computers or workstations(sometimes called fat clients)running Windows 9x,Windows NT,OS/2,or Macintosh OS.Any system interfaces are either executed on the server or across the network on another server.The user interface(usually graphical)is stored and executed on the client.All business logic is programmed to execute on the client using a PC-based programming language.All data is stored on the server and all file and database access and update commands and instructions are executed on the server computer.A database server is usually microprocessor-based(e.g.,UNIX or Windows/NT Server)but could still be a mainframe or minicomputer.Distributed DatabaseComputingThe clients are personal computers or workstations(sometimes called fat clients)running Windows 9x,Windows NT,OS/2,or Macintosh OS.Any system interfaces are either executed on the server or across the network on another server.The user interface(usually graphical)is stored and executed on the client.Some business logic may be programmed to execute on the client.Most business logic is programmed to execute on the server.Typically.data and business logic(and possibly other services)are on separate servers(same OSs as in previous column).Distributed Data/LogicComputingIn addition to fat clients(see previous column),some clients may be network computers(also called NCs or thin clients)that only execute downloaded programsUser interfaces may be stored and executed on the client,or downloaded from the Internet or intranet for execution on the client.System interfaces are managed from the Internet or intranet.Appropriate business logic may be downloaded from Inter/intranet server to execute on the client.Appropriate business logic is programmed to execute on the server.All data is stored on the server(possibly multiple servers)and all file and database access and update commands and instructions are executed on the server computers.Utilizes data and/or file servers as in previous two columns,but adds one or more Internet and intranet servers.Internet/IntranetComputingWhat is the server and operating system?The server is usually a minicomputer or mainframe,possibly networked to other minicomputers or mainframes.The server is usually a minicomputer(e.g.,OS/400 OS)or mainframe computer(e.g.MVS,VM,or UNIX OS).WideAreaNetworkWideAreaNetworkLocalAreaNetworkWideAreaNetworkLocalAreaNetworkThe user interface(usually graphical)is stored and executed on the client.All data is stored on the server(possibly multiple servers)and all file and database access and update commands and instructions are executed on the server computers.LocalAreaNetworkIntranetorInternetLocal orWide AreaNetwork11Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Centralized Computing:8Centralized process architectures were once dominant because the cost of placing computers closer to the end-user was prohibitive.8Many(if not most)legacy applications remain centralized on large mainframe computers(such as IBMs S/370 and 3090 families of computers)or smaller minicomputers(such as IBMs AS/400).12Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Presentation:8This alternative builds upon and enhances centralized computing applications.8The old character user interfaces are stripped from the centralized applications and regenerated as graphical user interfaces that will run on the PC.8The user interface(or presentation)is distributed off the server and onto the client.8All other elements of the centralized application remain on the server,but the system users get a friendlier graphical user interface to the system.13Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Presentation:8Distributed presentation computing advantages:It can be implemented relatively quickly since most aspects of the legacy application remain unchanged.Users get a friendly and familiar interface to existing systems The useful lifetime of legacy applications can be extended until such a time as resources warrant a wholesale redevelopment of the application.8Distributed presentation computing disadvantages:The applications functionality cannot be significantly improved,and the solution does not maximize the potential of the clients desktop computer by only dealing with the user interface.14Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Data:8Sometimes called two-tiered client/server.8This architecture places the information systems stored data on a server,and the business logic and user interfaces on the clients.8A local or wide area network usually connects the clients to the server.A local area network(or LAN)is a set of client computers(usually PCs)connected to one or more server computers(usually microprocessor-based,but could also include mainframes or minicomputers)through cable over relatively short distances.A wide area network(or WAN)is an interconnected set of LANs,or the connection of PCs over a longer distance.15Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Data:8The database server is fundamental to this architecture and its technology is different from a file server.File servers store the database,but the client computers must execute all database instructions.This means that entire databases and tables may have to be transported to and from the client across the network.Database servers also store the database,but the database commands are also executed on those servers.The clients merely send their database commands to the server.The server only returns the result of the database command processing not entire databases or tables.Thus,database servers generate much less network traffic.16Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Data:8The clients in the distributed database solution typically run the business logic of the information system application.8Distributed data computing advantages:Separates data and business logic to(1)isolate each from changes to the other,(2)make the data more available to users,and(3)retain the data integrity of centralized computing through centrally managed servers.8Distributed data computing disadvantages:The application logic must be maintained on all of the clients.17Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Data and Logic:8Referred to as three-tiered or n-tiered client/server computing.8This approach distributes databases and business logic to separate servers.8Uses the same database server(s)as in the two-tiered approach.8Uses an application server.The application server provides a transaction monitor such as to manage transactions.Some or all of the business logic of the application can be moved from the client to the application server.8Only the user interface and some relatively stable or personal business logic need be executed on the clients.18Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing Distributed Data and Logic:8Distributed data and logic computing disadvantages:Very complex to design and development.The most difficult aspect of three-tier client/server application design is partitioning.Partitioning is the act of determining how to best distribute or duplicate application components(data,process,and interfaces)across the network.19Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing The Internet and Intranets:8The Internet is an(but not necessarily the)information superhighway that permits computers of all types and sizes,all over the world to exchange data and information using standard languages and protocols.8An intranet is a secure network,usually corporate,that uses Internet technology to integrate desktop,workgroup,and enterprise computing into a single cohesive framework.The intranet provides management and users with a common interface to applications and information20Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing The Internet and Intranets:8Java is a cross-platform programming language designed specifically to exploit the Internet standards.Java applets(modular software components)are stored on an Internet or intranet server and downloaded to the client when they access the application.Java applets can execute on any client computing platform.8A network computer(or NC)is designed to only run Internet-based applications(such as web browsers and Java applets).The NC(also called a thin client)is simpler,and much cheaper than personal computers(increasingly called a fat client).21Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing The Role of Network Technologies:8The well designed network provides connectivity and interoperability.Connectivity defines how computers are connected to“talk”to one another.Interoperability is an ideal state in which connected computers cooperate with one another in a manner that is transparent to their users(the clients).Network topology describes how a network provides connectivity between the computers on that network.22Application Architecture&Process DesignData and DB process on serverAll business logic on the mainframe serverAll data on the mainframe serverBusiness logic on application serverUser Interface on the PC ClientNetworkLogic&user interface on PC NetworkData on DB process on ServerUser interface on the PC clientNetworkNetworkSome logic on Intranet ServerData on database serverInternal user interface on PCNetwork Secure intranet provides access to data,logic,and interfacesDistributed PresentationDistributed Data(2-tier)Distributed Data&Logic(3-tier)Internet and IntranetSome logic on Internet ServerExternal user PC clientInternet Connection provides access to interfaces and some logicSecure Gateway to protect applications and dataConnection to outside worldSecure connection to database server23Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing The Role of Network Technologies:8The Bus network topology:A direct point-to-point link between any two computer systems.The simplest network topology.The network can contain mainframes,minicomputers(or mid-range computers),personal computers,and dumb and intelligent terminals.To completely connect all points between n computers,you would need n times(n-1)/2 direct paths.Only one computer can send data through the bus at any given time.24Application Architecture&Process DesignInformation Technology Architecture:Network Architectures for Client/Server Computing The Role of Network Technologies:8The Ring network topology:Connects multiple computers and some peripherals into a ring-like structure.Each computer can transmit messages,instructions,and data(called packets)to only one other computer(or node on the network).Every transmission includes an address.When a computer receives a packet,it checks the address and if the packets address is different than the computers address,it passes it on to the next computer or node.Ring networks generally transmit packets in one direction;therefore,many computers can transmit at the same time to inc