Chapter 3. Database Architectures and the Web Transparencies

Transcription

1 Week 2: Chapter 3

2 Chapter 3 Database Architectures and the Web Transparencies

3 Database Environment - Objec<ves The meaning of the client server architecture and the advantages of this type of architecture for a DBMS. The difference between two- <er, three- <er and n- <er client server architectures. About cloud compu<ng and data as a service (DaaS) and database as a service (DBaaS). SoKware components of a DBMS. 3

4 Database Environment - Objec<ves The purpose of a Web service and the technological standards used to develop a Web service. The meaning of service- oriented architecture (SOA). The difference between distributed DBMSs, and distributed processing. The architecture of a data warehouse. About cloud compu<ng and cloud databases. The sokware components of a DBMS. 4

5 Mul<- user DBMS Architectures The common architectures that are used to implement mul<- user database management systems: Teleprocessing File- Server Client- Server 5

6 File- Server File- server is connected to several worksta<ons across a network. Database resides on file- server. DBMS and applica<ons run on each worksta<on. Disadvantages include: Significant network traffic. Copy of DBMS on each worksta<on. Concurrency, recovery and integrity control more complex. 6

7 Teleprocessing One computer with a single CPU and a number of terminals. Processing performed within the same physical computer. User terminals are typically dumb, incapable of func<oning on their own, and cabled to the central computer. 7

8 File- Server Architecture In a file- server environment, the processing is distributed about the network, typically a local area network (LAN). 8

9 Tradi<onal Two- Tier Client- Server Client (<er 1) manages user interface and runs applica<ons. Server (<er 2) holds database and DBMS. Advantages include: wider access to exis<ng databases; increased performance; possible reduc<on in hardware costs; reduc<on in communica<on costs; increased consistency. 9

10 Tradi<onal Two- Tier Client- Server 10

11 Alterna<ve Client- Server Topologies 11

12 Tradi<onal Two- Tier Client- Server 12

13 Three- Tier Client- Server 13

14 Web 3- Tier 14

15 Mobile 3- Tier 15

16 n- Tier Client- Server (e.g. 4- Tier) The three- <er architecture can be expanded to n <ers, with addi<onal <ers providing more flexibility and scalability. Applica<ons servers host API to expose business logic and business processes for use by other applica<ons. 16

17 N- Tier 17

18 First Genera3on web 18

19 Second Genera3on web 19

20 RIA Web Applica<ons HTML5 + CSS3 + JavaScript + JavaScript frameworks jquery jquery Mobile AngularJS Sencha EXT- JS SmartClient D3 Dart GWT (Google Web Toolkit) JavaFX 20

21 Middleware Middleware is a generic term used to describe sokware that mediates with other sokware and allows for communica<on between disparate applica<ons in a heterogeneous system. The need for middleware arises when distributed systems become too complex to manage efficiently without a common interface. 21

22 22

23 Middleware Remote Procedure Call (RPCs) Client makes calls to procedures running on remote systems. Message Oriented Middleware (MOM) Messages sent to the client are collected and stored un3l they are acted upon, while the client con3nues with other processing. Object Request Broker (ORB) This type of middleware makes it possible for applica3ons to send objects and request services in an object- oriented system. SQL- oriented Data Access middleware between applica3ons and database servers. 23

24 The Na<onal Ins<tute of Standards and Technology (NIST) provided a defini<on. Defined as A model for enabling ubiquitous, convenient, on- demand network access to a shared pool of configurable compu<ng resources (e.g. networks, servers, storage, applica<ons, and services) that can be rapidly provisioned and released with minimal management effort or service provider interac<on. 24

25 Transac<on Processing Monitor as middle <er of 3- <er client- server 25

26 Web Services and Service- Oriented Architectures Web service is a sokware system designed to support interoperable machine- to- web service machine interac<on over a network. Web services share business logic, data, and processes through a programma<c interface across a network. Developers can add the Web service to a Web page (or an executable program) to offer specific func<onality to users. 26

27 Web Services and Service- Oriented Architectures UDDI (Universal Discovery, Descrip3on, and Integra3on) protocol is a plaworm independent, XML- based registry for businesses to list themselves on the Internet. 27

28 Distributed DBMSs 28

29 Data Warehousing A data warehouse was deemed the solu<on to meet the requirements of a system capable of suppor<ng decision making, receiving data from mul<ple opera<onal data sources. 29

30 Cloud Compu<ng The Na<onal Ins<tute of Standards and Technology (NIST) provided a defini<on. Defined as A model for enabling ubiquitous, convenient, on- demand network access to a shared pool of configurable compu<ng resources (e.g. networks, servers, storage, applica<ons, and services) that can be rapidly provisioned and released with minimal management effort or service provider interac<on. 30

31 Cloud Compu<ng Key Characteris<cs On- demand self- service Consumers can obtain, configure and deploy cloud services without help from provider. Broad network access Accessible from anywhere, from any standardized placorm (e.g. desktop computers, laptops, mobile devices). 31

32 Data Warehousing / icloud 32

33 Data Warehousing / icloud 33

34 Cloud Compu<ng Comparison of Services Models 34

35 Cloud- based database solu<ons Mul<- tenant cloud database- shared server, separate database server process architecture. 35

36 Cloud- based database solu<ons Mul<- tenant cloud database- shared DBMS server, separate databases. 36

37 Cloud- based database solu<ons Mul<- tenant cloud database- shared DBMS server, separate databases. 37

38 Cloud- based database solu<ons Mul<- tenant cloud database shared database, separate schema architecture. 38

39 Components of a DBMS Query processor. Database manager (DM) File manager DML Recovery manager Buffer manager 39

40 Components of a DBMS 40

41 Components of Database Manager (DM) 41

42 In Class Qs

43 HWK