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Lecture 1: Basic Internet Concepts & Databases - the History. PROJECT Web-based Database Applications. From “local” database applications to “web-based” or web-enabled applications Characteristics Requirements Advantages / disadvantages Approaches, mechanisms, and tools ….
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Lecture 1: Basic Internet Concepts & Databases - the History PROJECT Web-based Database Applications
From “local” database applications to “web-based” or web-enabled applications • Characteristics • Requirements • Advantages / disadvantages • Approaches, mechanisms, and tools • …
Remote database access • What if you are in an airport and need to access the information stored on your DB? • Characteristics (limitations) of the traditional “local” database applications • What is needed to make it happen? • Geographical location independence • User interface • Access rights and security
History of Hypertext & Hypermedia - 1 Centralized Sequential text handling: • In 60s – Simple text • Print, store, edit, visualize • In 70s – Text processors (programs, text, etc.) • Interpreters • Reserved symbols, and characters • E.g. Vi , emacs
History of Hypertext & Hypermedia - 2 Sequential text handling: • Late 70s / early 80s – word processors (documents) • Centralized, User friendly • Interpreting symbols and commands • Troff, Nroff, Latex • Late 70s / early 80s – Internet • Network of computers around the world • Email • File transfer (ftp) • Telnet (login to remote computers)
History of Hypertext & Hypermedia - 3 Linking document blocks: • Mid 80s –Hypertext / Hyperlinks • Breaking the sequentiality • Interpreting symbols & commands + file names • Centralized • Hypercard on Mac. • Hyperlinks - file names (addresses) introducing links • Mid 80s – (S)GML (Generalized Mark-up Lang.) • Mark up language to describe Documents for formatting and printing
History of Hypertext & Hypermedia - 4 Linking document blocks: • Early 90s –Hypermedia • Hypertext + multi-media (audio, visual, …) • Early 90s – WWW • Generalization of hypermedia + internet • documents located at different network nodes • Hyperlinks also include the address of the machines • 2 physicists at CERN used hyperlinks over the internet, to exchange documents • Mid 90s – A graphical interface to fetch Docs from the WWW
History of Hypertext & Hypermedia - 5 Linking document blocks: • Mid 90s –Static HTML page • Special case of hypermedia / hyperlinks developed for WWW • Other languages also exist • Encyclopedia CD-ROMs’ mark ups are not HTML • The interpreter of the HTML (for www) is called a browser • A set of opening / closing tags format different parts of the HTML page
History of Hypertext & Hypermedia - 6 Towards Dynamic HTML pages: • late 90s / early 2000 – Dynamic HTML page • Applets (small applications)- code included within the HTML page (e.g. for animation, calculation of C to F) • Servlets - code written in JAVA-like language, exists outside the HTML page, referenced by the URL, requires a web server to run • CGIs - similar to Servlet, but written in any language
History of Hypertext & Hypermedia - 7 Internet Browsers: • In 90s – Browsers (e.g. Netscape and Explorer) • Paging the long HTML files • Support the interpretation of actions (in static & dynamic HTML pages) within the document • Preserve the security of the host machine: • For static actions (applets), make sure that the actions do not violate the host machine’s protection and security
History of Hypertext & Hypermedia - 8 Internet Browsers: • Browsers handling the execution of actions • Interpretation of actions within the HTML document: • local actions (static HTML page) • Read the time / date from the local machine • Animation • Exchange the format for temperature (from C to F) • Remote actions - accessing the server (dynamic HTML page) • Read / fetch information from the database • Calculate the exchange rate for currency (for today)
History of Hypertext & Hypermedia - 9 HTML page editors: HTML pages can be generated by: • Text editors (e.g. WORD, using the HTML manuals as the base) • Creating the formatted page in WORD, then using the converter from the WORD page to the HTML page [ save-asWEB page, then view the Source] • Use the tools to compose formatted web pages as a multi-media object [file, edit, MS word to automatically generate web page] • Fancy HTML page composers (e.g. the Front page)