Chapter 9:Application Design and Development Application Programs and User Interfaces Web Fundamentals Servlets and JSP Application Architectures Rapid Application Development Application Performance Application Security Encryption and Its Applications Database System Concepts-6th Edition 9.2 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.2 ©Silberschatz, Korth and Sudarshan th Edition Chapter 9: Application Design and Development Application Programs and User Interfaces Web Fundamentals Servlets and JSP Application Architectures Rapid Application Development Application Performance Application Security Encryption and Its Applications
Application Programs and User Interfaces Most database users do not use a query language like SQL An application program acts as the intermediary between users and the database Applications split into front-end middle layer backend Front-end:user interface Forms Graphical user interfaces Many interfaces are Web-based Database System Concepts-6th Edition 9.3 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.3 ©Silberschatz, Korth and Sudarshan th Edition Application Programs and User Interfaces Most database users do not use a query language like SQL An application program acts as the intermediary between users and the database Applications split into front-end middle layer backend Front-end: user interface Forms Graphical user interfaces Many interfaces are Web-based
Application Architecture Evolution Three distinct era's of application architecture mainframe(1960's and 70's) personal computer era(1980's) We era(1990's onwards) Terminals Desktop PCs Web browsers Application Application Program Program Propietary Network or dial up phone lines Local Area Network Internet Mainframe Computer Web Application Server Database Database (a)Mainframe Era (b)Personal Computer Era (c)Web era Database System Concepts-6th Edition 9.4 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.4 ©Silberschatz, Korth and Sudarshan th Edition Application Architecture Evolution Three distinct era’s of application architecture mainframe (1960’s and 70’s) personal computer era (1980’s) We era (1990’s onwards)
Web Interface Web browsers have become the de-facto standard user interface to databases Enable large numbers of users to access databases from anywhere Avoid the need for downloading/installing specialized code,while providing a good graphical user interface Javascript,Flash and other scripting languages run in browser,but are downloaded transparently Examples:banks,airline and rental car reservations,university course registration and grading,an so on. Database System Concepts-6th Edition 9.5 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.5 ©Silberschatz, Korth and Sudarshan th Edition Web Interface Web browsers have become the de-facto standard user interface to databases Enable large numbers of users to access databases from anywhere Avoid the need for downloading/installing specialized code, while providing a good graphical user interface Javascript, Flash and other scripting languages run in browser, but are downloaded transparently Examples: banks, airline and rental car reservations, university course registration and grading, an so on
The World Wide Web The Web is a distributed information system based on hypertext. Most Web documents are hypertext documents formatted via the HyperText Markup Language(HTML) HTML documents contain text along with font specifications,and other formatting instructions hypertext links to other documents,which can be associated with regions of the text. forms,enabling users to enter data which can then be sent back to the Web server Database System Concepts-6th Edition 9.6 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.6 ©Silberschatz, Korth and Sudarshan th Edition The World Wide Web The Web is a distributed information system based on hypertext. Most Web documents are hypertext documents formatted via the HyperText Markup Language (HTML) HTML documents contain text along with font specifications, and other formatting instructions hypertext links to other documents, which can be associated with regions of the text. forms, enabling users to enter data which can then be sent back to the Web server
Uniform Resources Locators In the Web,functionality of pointers is provided by Uniform Resource Locators (URLs). URL example: http://www.acm.org/sigmod The first part indicates how the document is to be accessed "http"indicates that the document is to be accessed using the Hyper Text Transfer Protocol. The second part gives the unique name of a machine on the Internet. The rest of the URL identifies the document within the machine. The local identification can be: The path name of a file on the machine,or An identifier(path name)of a program,plus arguments to be passed to the program -E.g.,http://www.google.com/search?q=silberschatz Database System Concepts-6th Edition 9.7 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.7 ©Silberschatz, Korth and Sudarshan th Edition Uniform Resources Locators In the Web, functionality of pointers is provided by Uniform Resource Locators (URLs). URL example: http://www.acm.org/sigmod The first part indicates how the document is to be accessed “http” indicates that the document is to be accessed using the Hyper Text Transfer Protocol. The second part gives the unique name of a machine on the Internet. The rest of the URL identifies the document within the machine. The local identification can be: The path name of a file on the machine, or An identifier (path name) of a program, plus arguments to be passed to the program – E.g., http://www.google.com/search?q=silberschatz
HTML and HTTP HTML provides formatting,hypertext link,and image display features including tables,stylesheets(to alter default formatting),etc. HTML also provides input features Select from a set of options -Pop-up menus,radio buttons,check lists Enter values -Text boxes Filled in input sent back to the server,to be acted upon by an executable at the server HyperText Transfer Protocol(HTTP)used for communication with the Web server Database System Concepts-6th Edition 9.8 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.8 ©Silberschatz, Korth and Sudarshan th Edition HTML and HTTP HTML provides formatting, hypertext link, and image display features including tables, stylesheets (to alter default formatting), etc. HTML also provides input features Select from a set of options – Pop-up menus, radio buttons, check lists Enter values – Text boxes Filled in input sent back to the server, to be acted upon by an executable at the server HyperText Transfer Protocol (HTTP) used for communication with the Web server
Sample HTML Source Text IDNameDepartment 00128ZhangComp.Sci. Search for: Student Instructor Name: Database System Concepts-6th Edition 9.9 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.9 ©Silberschatz, Korth and Sudarshan th Edition Sample HTML Source Text ID Name Department 00128 Zhang Comp. Sci. …. Search for: Student Instructor Name:
Display of Sample HTML Source ID Name Department 00128 Zhang Comp.Sci. 12345 Shankar Comp.Sci. 19991 Brandt History Search for: Student Name: submit Database System Concepts-6th Edition 9.10 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.10 ©Silberschatz, Korth and Sudarshan th Edition Display of Sample HTML Source
Web Servers A Web server can easily serve as a front end to a variety of information services. The document name in a URL may identify an executable program,that,when run,generates a HTML document. When an HTTP server receives a request for such a document,it executes the program,and sends back the HTML document that is generated. The Web client can pass extra arguments with the name of the document. To install a new service on the Web,one simply needs to create and install an executable that provides that service. The Web browser provides a graphical user interface to the information service. Common Gateway Interface(CGl):a standard interface between web and application server Database System Concepts-6th Edition 9.11 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 9.11 ©Silberschatz, Korth and Sudarshan th Edition Web Servers A Web server can easily serve as a front end to a variety of information services. The document name in a URL may identify an executable program, that, when run, generates a HTML document. When an HTTP server receives a request for such a document, it executes the program, and sends back the HTML document that is generated. The Web client can pass extra arguments with the name of the document. To install a new service on the Web, one simply needs to create and install an executable that provides that service. The Web browser provides a graphical user interface to the information service. Common Gateway Interface (CGI): a standard interface between web and application server