5 Chapter 3 - ObjectivesThe purpose of a Web service and the technological standards usedThe meaning of service-oriented architecture (SOA)The difference between distributed DBMSs, and distributed processingThe architecture of a data warehouseThe software components of a DBMSAbout Oracle’s logical and physical structure
6 Multi-user DBMS Architectures TeleprocessingTraditional architecture for multi-user systemsOne computer with a single central processing unit (CPU) and a number of terminalsPut a huge burden on the central computerDownsizingReplacing expensive mainframe computers with more cost-effective networks of personal computers
7 Multi-user DBMS Architectures File-server architectureProcessing is distributed about the networkThree main disadvantagesLarge amount of network trafficFull copy of DBMS required on each workstationConcurrency, recovery, and integrity control are complexMultiple DBMSs can access the same files
9 Multi-user DBMS Architectures Traditional two-tier client–server architectureClient process requires some resourceServer provides the resourceBasic separation of four main components of business applicationTypical interaction between client and server
10 Traditional Two-Tier Client-Server Client (tier 1) manages user interface and runs applications.Server (tier 2) holds database and DBMS.Advantages include:wider access to existing databases;increased performance;possible reduction in hardware costs;reduction in communication costs;increased consistency.
13 Multi-user DBMS Architectures Three-tier client–server architectureUser interface layerBusiness logic and data processing layerDBMSMany advantages over traditional two-tier or single-tier designs
14 Three-Tier Client-Server Client side presented two problems preventing true scalability:‘Fat’ client, requiring considerable resources on client’s computer to run effectively.Significant client side administration overhead.By 1995, three layers proposed, each potentially running on a different platform.
15 Three-Tier Client-Server Advantages:‘Thin’ client, requiring less expensive hardware.Application maintenance centralized.Easier to modify or replace one tier without affecting others.Separating business logic from database functions makes it easier to implement load balancing.Maps quite naturally to Web environment.
17 Multi-user DBMS Architectures N-tier architecturesThree-tier architecture can be expanded to n tiersApplication serversHosts an application programming interface (API) to expose business logic and business processes for use by other applications
19 Multi-user DBMS Architectures MiddlewareSoftware that mediates with other softwareCommunication among disparate applicationsSix main typesAsynchronous Remote Procedure Call (RPC)Synchronous RPCPublish/SubscribeMessage-Oriented middleware (MOM)Object-request broker (ORB)SQL-oriented data access
20 Multi-user DBMS Architectures Transaction processing monitorControls data transfer between clients/serversProvides a consistent environment, particularly for online transaction processing (OLTP)Significant advantagesTransaction routingManaging distributed transactionsLoad balancingFunnelingIncreased reliability
21 Transaction Processing Monitors Program that controls data transfer between clients and servers in order to provide a consistent environment, particularly for Online Transaction Processing (OLTP).
23 Web Services and Service-Oriented Architectures Software system that supports interoperable machine-to-machine interaction over a networkNo user interfaceExamples of Web servicesUses widely accepted technologies and standards
25 Web Services and Service-Oriented Architectures Service-Oriented Architectures (SOA)Architecture for building applications that implement business processes as sets of servicesPublished at a granularity relevant to the service consumerLoosely coupled and autonomous servicesWeb services designed for SOA different from other Web services
27 Distributed DBMSs Distributed database Logically interrelated collection of shared data physically distributed over a computer networkDistributed DBMSSoftware system that permits the management of the distributed databaseMakes the distribution transparent to users
28 Distributed DBMSs Characteristics of DDBMS Collection of logically related shared dataData split into fragmentsFragments may be replicatedFragments/replicas are allocated to sitesSites are linked by a communications networkData at each site is controlled by DBMSDMBS handles local apps autonomouslyEach DBMS in one or more global app
29 Distributed DBMSs Distributed processing Centralized database that can be accessed over a computer networkSystem consists of data that is physically distributed across a number of sites in the network
30 Data Warehousing Data warehouse Consolidated/integrated view of corporate dataDrawn from disparate operational data sourcesRange of end-user access tools capable of supporting simple to highly complex queries to support decision makingSubject-oriented, integrated, time-variant, and nonvolatile
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