Presentation on theme: "Centralized and Client/Server Architecture and Classification of DBMS"— Presentation transcript:
1 Centralized and Client/Server Architecture and Classification of DBMS Database SystemsLecture 7Centralized and Client/Server Architecture and Classification of DBMSDatabase Management SystemsToqir Ahmad Rana
2 Today’s agenda Centralized and Client/Server Architecture for DBMS Database Management SystemsToqir Ahmad RanaToday’s agendaCentralized and Client/Server Architecture for DBMSBasic client/server architectureTwo –tier client/server architectureThree –tier client/server architectureClassification of DBMS
3 Centralized and Client-Server Architectures Database Management SystemsToqir Ahmad RanaCentralized and Client-Server ArchitecturesCentralized DBMS: combines everything into single system including- DBMS software, hardware, application programs and user interface processing software.
4 A physical centralized architecture. Database Management SystemsToqir Ahmad RanaA physical centralized architecture.
5 Basic Client-Server Architectures Database Management SystemsToqir Ahmad RanaBasic Client-Server ArchitecturesSpecialized Servers with Specialized functionsClientsDBMS Server
6 Specialized Servers with Specialized functions: Database Management SystemsToqir Ahmad RanaSpecialized Servers with Specialized functions:File ServersPrinter ServersWeb ServersServers
7 Database Management Systems Toqir Ahmad RanaClients:Provide appropriate interfaces and a client- version of the system to access and utilize the server resources.Clients maybe diskless machines or PCs or Workstations with disks with only the client software installed.Connected to the servers via some form of a network (LAN: local area network, wireless network, etc.)
11 Two Tier Client-Server Architecture Database Management SystemsToqir Ahmad RanaTwo Tier Client-Server ArchitectureUser Interface Programs and Application Programs run on the client sideInterface called ODBC (Open Database Connectivity ) provides an Application program interface (API) allow client side programs to call the DBMS. Most DBMS vendors provide ODBC drivers.
12 Two Tier Client-Server Architecture Database Management SystemsToqir Ahmad RanaTwo Tier Client-Server ArchitectureA client program may connect to several DBMSs.Other variations of clients are possible: e.g., in some DBMSs, more functionality is transferred to clients including data dictionary functions, optimization and recovery across multiple servers, etc. In such situations the server may be called the Data Server.
13 Three Tier Client-Server Architecture Database Management SystemsToqir Ahmad RanaThree Tier Client-Server ArchitectureCommon for Web applicationsIntermediate Layer called Application Server or Web Server:stores the web connectivity software and the rules and business logic (constraints) part of the application used to access the right amount of data from the database serveracts like a conduit for sending partially processed data between the database server and the client.Additional Features- Security:encrypt the data at the server before transmissiondecrypt data at the client
15 Classification of DBMSs Database Management SystemsToqir Ahmad RanaClassification of DBMSsSeveral criteria are normally used to classify DBMSs.Data modelNumber of usersNumber of sitesCostTypes of access path
16 Database Management Systems Toqir Ahmad RanaData ModelRelational model represents a database as a collection of tables, where each table can be stored as a separate file.Object model defines a database in terms of objects, their properties, and their operations.Relational DBMSs have been extending their models to incorporate object database concepts and other capabilities; Object-relational modelHierarchical model represents data as record typesand also represents a limited type of l:N relationship, called a set type.Network model represents data as hierarchical tree structures.
17 The schema of Figure 2.1 in network model notation Database Management SystemsToqir Ahmad RanaThe schema of Figure 2.1 in network model notation
18 Database Management Systems Toqir Ahmad RanaNumber of usersSingle-user systems support only one user at a time and are mostly used with personal computers.Multiuser systems, which include the majority of DBMSs, support multiple users concurrently.
19 Database Management Systems Toqir Ahmad RanaNumber of sitesA DBMS is centralized if the data is stored at a single computer site.A distributed DBMS (DDBMS) can have the actual database and DBMS software distributed over many sites, connected by a computer network.HomogeneousHeterogeneousFederated or Multidatabase Systems
20 Types of the access path Database Management SystemsToqir Ahmad RanaTypes of the access pathOne well-known family of DBMSs is based on inverted file structures. Finally, a DBMS can be general purpose or special purpose.Online transaction processing (OLTP) systems,