Sistem Basis Data Lanjut. Sistem Manajemen Basis Data Web

Transkripsi

1 Sistem Manajemen Basis Data Web Tim Penyusun : Pengajar Universitas Gunadarma 2008

2 Outline Web sebagai Platform Aplikasi Basis Data Data semi terstruktur Pengenalan XML Bahasa Queri XML SMBD - Web 2

3 Internet Interconnected Networks Kumpulan dari jaringan komputer di seluruh dunia yg saling terhubung via TCP(Transmission Control Protocol), IP(Internet Protocol) TCP bertanggungjawab menjamin pengiriman pesan dari satu komputer dgn yg lain, secara benar. IP mengelola pengiriman dan penerimaan paket data antara satu mesin dgn yg lain. SMBD - Web 3

4 Sejarah Internet Mulai dibangun pada thn 60an & 70an oleh Departemen Pertahanan AS. disebut ARPANET (Advanced Research Projects Agency NETwork) Poyek membangun jaringan yg dapat menahan serangan secara fisik. 1982: TCP/IP diadopsi sebagai protocol standar untuk ARPANET 1986: proyek dipindahkan dari militer ke pemerintahan/universitas dengan dana National Science Foundation Disebut NSFNET (National Science Foundation NETwork) 1995: NSFNET mengakhiri pengontrolan backbone jaringan; jaringan/network kemudian dikenal dengan Internet. SMBD - Web 4

5 Intranet & Extranet Intranet : suatu web site atau kumpulan web site dari suatu organisasi, yg dapat diakses hanya oleh anggota dari organisasi tersebut (via firewall) Extranet : intranet yg dapat diakses sebagian oleh pengguna (diberi otoritas) di luar organisasi SMBD - Web 5

6 ecommerce & ebusiness ecommerce Pelanggan dapat menempatkan & membayar pesanan via web site ebusiness Integrasi yg lengkap dari tehnologi internet ke dalam infrastruktur ekonomi bisnis Ecosystem Proses bisnis secara keseluruhan diotomatisi, dimana pemasok, alliance partners, corporate infrastructure merged into seamless system SMBD - Web 6

7 Web Sistem berbasis hipermedia, yg menyediakan point and click berarti browsing informasi pada internet menggunakan hyperlink Informasi pada halaman Web terdiri atas teks, grafik, gambar, & suara. Terdapat pula hyperlink ke halaman web lainnya, dimana pengguna dapat menelusuri dengan cara nonsekuensial melalui informasi. Dokumen2 web ditulis menggunakan HTML. SMBD - Web 7

8 Web (lanj.) Web terdiri atas jaringan komputer yg dpt berperan sebagai Server, menyediakan informasi; Contoh, Apache HTTP Server, Microsoft Internet Information Server, Netscape Enterprise Server, WebLogic Server & NCSA HTTPd Client (browsers), memohon informasi. Contoh, Microsoft Internet Explorer, Netscape Navigator & NCSA Mosaic SMBD - Web 8

9 Web (lanj.) Protocol yg mengatur pertukaran informasi antara server & browser web adalah HTTP Lokasi dengan dokumen2 diidentifikasikan sebagai URL. SMBD - Web 9

10 Komponen Dasar Web SMBD - Web 10

11 HyperText Transfer Protocol (HTTP) Protokol yg digunakan untuk mentransfer halaman web melalui internet. Berbasis paradigma requestresponse : Connection - Client berkoneksi dengan Web server. Request - Client mengirim permohonan ke web server. Response web server mengirim respon (dokumen HTML) pada client. Close - Koneksi ditutup oleh web server. SMBD - Web 11

12 MIME types Multipurpose Internet Mail Extensions Digunakan oleh HTTP header utk menentukan penanganan tipe media yg multipel Contoh: teks/html (dokumen html; *.html) aplikasi/java (java class file; *.class) SMBD - Web 12

13 HTTP Request HTTP header mengindikasikan : 1. Tipe permohonan GET: mendapat sumber yg diminta POST: mentransfer data ke data yg posted data pada sumber tertentu HEAD: sama seperti GET tapi hanya mengembalikan HTTP header PUT (HTTP/1.1): upload sumber ke server DELETE (HTTP/1.1): menghapus sumber dari server OPTIONS (HTTP/1.1):memohon pilihan konfigurasi server 2. Nama sumber 3. Versi HTTP 4. body (*optional) SMBD - Web 13

14 HTTP Response HTTP header mengindikasikan: 1. Versi HTTP 2. Status respon 3. Informasi utk mengontrol perilaku respon 4. body (*optional) SMBD - Web 14

15 HyperText Markup Language (HTML) Bahasa yg memformat dokumen digunakan utk merancang halaman web. Bahasa yg sederhana, punya kekuatan, bahasa dokumen yg tidak bergantung pada platform tertentu. HTML merupakan aplikasi dari Standardized Generalized Markup Language (SGML), sistem yg mendefinisikan tipe dokumen yg terstruktur & markup language utk merepresentasikan instance2 dari tipe2 dokumen tsb. SMBD - Web 15

16 Contoh File HTML SMBD - Web 16

17 Contoh Halaman HTML SMBD - Web 17

18 Uniform Resource Locators (URLs) URL terdiri atas 3 bagian: protokol yg digunakan utk koneksi Nama host Nama path pada host dimana sumber disimpan. Can optionally specify: port through which connection to host should be made, query string. tml SMBD - Web 18

19 Kebutuhan Untuk Integrasi Web-DBMS Kemampuan utk mengakses data yg berharga dengan cara yg aman. Konektivitas data & vendor yg tidak bergantung sehingga terdapat kebebasan untuk memilih DBMS. Ability to interface to database independent of any proprietary browser or Web server. Connectivity solution that takes advantage of all the features of an organization s DBMS. SMBD - Web 19

20 Open architecture to allow interoperability with a variety of systems and technologies. For example: different Web servers; Microsoft's (Distributed) Common Object Model (DCOM/COM); CORBA/IIOP (Internet Inter-ORB protocol); Java/Remote Method Invocation (RMI). Cost-effective solution that allows for scalability, growth, and changes in strategic directions, and helps reduce applications development costs. SMBD - Web 20

21 Arsitektur Two-Tier Client-Server SMBD - Web 21

22 Arsitektur 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. SMBD - Web 22

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24 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. SMBD - Web 24

25 Advantages of Web-DBMS Approach Web sebagai platform sistem basis data DBMS advantages Simplicity Platform independence Graphical User Interface Standardization Cross-platform support Transparent network access Scalable deployment Innovation SMBD - Web 25

26 Disadvantages of Web-DBMS Approach Reliability Security Cost Scalability Limited functionality of HTML Statelessness Bandwidth Performance Immaturity of development tools SMBD - Web 26

27 Pendekatan2 Untuk Mengintegrasikan Web & SMBD Scripting Languages. Common Gateway Interface (CGI). HTTP Cookies. Extending the Web Server. Java, JDBC, SQLJ, Servlets, and JSP. Microsoft Web Solution Platform: ASP and ADO. Oracle Internet Platform. SMBD - Web 27

28 Scripting Languages (JavaScript and VBScript) Scripting languages can be used to extend browser and Web server with database functionality. As script code is embedded in HTML, it is downloaded every time page is accessed. Updating browser is simply a matter of changing Web document on server. Some popular scripting languages are: JavaScript, VBScript, Perl, and PHP. They are interpreted languages, not compiled, making it easy to create small applications. SMBD - Web 28

29 Common Gateway Interface (CGI) Specification for transferring information between a Web server and a CGI program. Server only intelligent enough to send documents and to tell browser what kind of document it is. But server also knows how to launch other programs. When server sees that URL points to a program (script), it executes script and sends back script s output to browser as if it were a file. SMBD - Web 29

30 CGI - Environment SMBD - Web 30

31 CGI defines how scripts communicate with Web servers. A CGI script is any script designed to accept and return data that conforms to the CGI specification. Before server launches script, prepares number of environment variables representing current state of the server, who is requesting the information, and so on. Script picks this up and reads STDIN. SMBD - Web 31

32 Then performs necessary processing and writes its output to STDOUT. Script responsible for sending MIME header, which allows browser to differentiate between components. CGI scripts can be written in almost any language, provided it supports reading and writing of an operating system s environment variables. SMBD - Web 32

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34 CGI is the de facto standard for interfacing Web servers with external applications. Possibly most commonly used method for interfacing Web applications to data sources. Advantages: simplicity, language independence, Web server independence, wide acceptance. SMBD - Web 34

35 Keuntungan CGI Communication between client and database server must always go through Web server. Lack of efficiency and transaction support, and difficulty validating user input inherited from statelessness of HTTP protocol. HTTP never intended for long exchanges or interactivity. Server has to generate a new process or thread for each CGI script. Security. SMBD - Web 35

36 HTTP Cookies Cookies can make CGI scripts more interactive. Cookies are small text files stored on Web client. CGI script creates cookie and has Web server send it to client s browser to store on hard disk. Later, when client revisits Web site and uses a CGI script that requests this cookie, client s browser sends information stored in the cookie. Cookies can be used to store registration information or preferences (e.g. for virtual shopping cart). However, not all browsers support cookies. SMBD - Web 36

37 Integrasi SMBD & Web SMBD - Web 37

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42 Referensi 1. Korth, H.; Database System Concept, Mc Graw Hill, 4th edition, New York, 2002 SMBD - Web 42