HTML Basics Quiz

Web Technology and DBMS

• HTML is a system for marking up documents for publishing on the Web, developed by Tim Berners-Lee and standardized as HTML version 2 in 1995.
• The World Wide Web Consortium (W3C) currently recommends the use of HTML 4.01 and produced XHTML 1.0 as a reformulation of HTML 4 in XML.
• Uniform Resource Locators (URLs) represent the location or address of a resource on the Internet and define where documents can be found, while Uniform Resource Identifiers (URIs) and Uniform Resource Names (URNs) are related terms for referring to Internet resources.
• URLs are the most commonly used identification scheme for resources on the Internet and are the basis for HTTP and the Web.
• Static web pages have fixed content, while dynamic web pages generate content each time they are accessed, allowing for user input and customization.
• Dynamic web pages can respond to user input, be customized for each user, and are generated by the server, often through scripts that convert data into HTML on the fly.
• Web services are based on open standards and focus on communication and collaboration among people and applications, without a user interface and aimed at browsers.
• Web services consist of reusable software components designed to be consumed by other applications, such as client applications, web-based applications, or other web services.
• Many organizations require a general solution for integrating database applications with the Web to prevent being tied to one technology, with requirements such as secure data access, vendor-independent connectivity, and support for various technologies.
• Requirements for web-DBMS integration include secure data access, vendor-independent connectivity, interfacing to the database independent of any proprietary web browser or server, and an open-architecture approach for interoperability.
• Other requirements for web-DBMS integration include cost-effectiveness, scalability, support for transactions spanning multiple HTTP requests, session- and application-based authentication, acceptable performance, and minimal administration overhead.
• Additionally, a set of high-level productivity tools is needed to allow for the development, maintenance, and deployment of applications with ease and speed.

Integrating Web and DBMS Technologies

• Current approaches to integrating databases into the Web environment include scripting languages, Common Gateway Interface (CGI), HTTP cookies, and extensions to the Web server.
• Scripting languages like JavaScript and VBScript allow the creation of functions embedded within HTML code, automating processes and manipulating objects.
• JavaScript and JScript are virtually identical interpreted scripting languages from Netscape and Microsoft, respectively, used for scripting within an HTML document.
• VBScript, a Microsoft proprietary interpreted scripting language, has syntax more like Visual Basic than Java and is procedural in nature.
• Common Gateway Interface (CGI) is a specification for transferring information between a Web server and a CGI program, allowing the server to launch other programs and execute scripts.
• HTTP cookies are pieces of information stored by the client on behalf of the server, allowing the server to identify the user and personalize the appearance of the web page.
• CGI scripts can be made more interactive by using cookies, as the client may have many cookies stored at any given time, each associated with a particular website or web page.
• Cookies have an expiration date, and if explicitly set to some time in the future, the browser will automatically save the cookie to the client’s hard drive.
• Extensions to the Web server, such as the Netscape API (NSAPI) and Microsoft’s Internet Information Server API (ISAPI), provide additional functionality for integrating databases into the Web environment.
• Java, JEE, JDBC, SQLJ, JDO, JPA, Servlets, JavaServer Pages (JSP), .NET, Active Server Pages (ASP), and ActiveX Data Objects (ADO) are also used for integrating databases into the Web environment.
• JavaScript, VBScript, Perl, and PHP are interpreted scripting languages that provide the key functions needed to retain a “thin” client application and promote rapid application development.
• Most of the hype in this area focuses on Java, but scripting engines are likely to supply important day-to-day functionality for integrating databases into the Web environment.

Web Technology and Database Management Systems Overview

• Cookies are used to identify requests from the same user, allowing retrieval of user-specific information from a database.
• CGI is a method for supporting application-specific functionality, but it has limitations related to performance and handling of shared resources.
• Non-CGI gateways, such as Microsoft’s Internet Information Server API (ISAPI) and Apache Web Server API, aim to overcome CGI limitations.
• Java, initially developed by Sun Microsystems, has become one of the most popular programming languages for Web computing.
• JDBC provides a prominent approach for accessing relational DBMSs from Java, supporting basic SQL functionality.
• The EJB 2.0 specification introduced Container-Managed Persistence (CMP), Container-Managed Relationships (CMR), and the EJB Query Language (EJB-QL).
• Java servlets offer improved performance, portability, and extensibility compared to CGI programming.
• Servlets also provide simpler session management and improved security and reliability due to the built-in Java security model.
• Microsoft’s Web Platform, Microsoft.NET, envisions software delivery as a service accessible from any device, any time, and any place.
• Microsoft Open Database Connectivity (ODBC) technology provides a common interface for accessing heterogeneous SQL databases.
• ODBC, based on SQL, offers a high degree of interoperability, allowing a single application to access different SQL DBMSs through a common set of code.