System Analysis and Design System Design - Mr. Ahmad Al-Ghoul In this sequence we will discuss the components of a database management system, then we will Describe Web-based data design

System Analysis and Design System Design learning Objectives Understand the components of a database management system (DBMS) Describe Web-based data design, including characteristics of Web-Based Design, Internet terminology, connecting a Database to the Web, and data Security Avicenna System Analysis and Design System Design

System Analysis and Design System Design DBMS Components A DBMS provides an interface between a database and users who need to access the data In addition to interfaces for users, database administrators, and related systems, a DBMS also has a data manipulation language, a schema and subschemas, and a physical data repository Avicenna System Analysis and Design System Design

System Analysis and Design System Design DBMS Components Interfaces for Users, Database Administrators, and Related Systems When users, database administrators, and related information systems request data and services, the DBMS processes the request, manipulates the data, and provides a response Users: typically work with predefined quires and switchboard commands, but also use a query language to access stored data Query language: A query language allows a user to specify a task without specifying how the task will be accomplished. Some query languages use natural language commands that resemble ordinary English sentences. SQL (structured query language): is a query language that allows PC users to communicate with servers and mainframe computers. Avicenna System Analysis and Design System Design

System Analysis and Design System Design DBMS Components Interfaces for Users, Database Administrators, and Related Systems Database Administrators A DBA is responsible for DBMS management and support DBA is concerned with data security and integrity, preventing unauthorized access, providing backup and recovery, audit trails, maintaining the database, and supporting users needs Related information systems A DBMS can support several related information systems that provide input to, and require specific data from, the DBMS A data manipulation language (DML) controls database operations, including storing, retrieving, updating, and deleting data Commands in this category allow you to manipulate data in existing database objects. The most popular commands in this category are INSERT, UPDATE, and DELETE. Avicenna System Analysis and Design System Design

System Analysis and Design System Design DBMS Components Schema The complete definition of a database, including descriptions of all fields, tables, and relationships, is called a schema You also can define one or more subschemas. A subschema is a view of the database used by one or more systems or users. A subschema defines only those portions of the database that a particular system or user needs or is allowed to access. Avicenna System Analysis and Design System Design

System Analysis and Design System Design DBMS Components Physical Data Repository The data dictionary which describes all data elements included in the logical design, is transformed into a physical data repository, which also contains the schema and subschemas The physical repository might be centralized, or distributed at several locations To resolve potential database connectivity and access problems, companies use ODBC – open database connectivity: is an industry-standard protocol that makes it possible for software from different vendors to interact and exchange data uses SQL statements JDBC – Java database connectivity: JDBC enables Java applications to exchange data with any database that uses SQL statements and is JDBC-compliant Avicenna System Analysis and Design System Design

Web-Based Database Design Characteristics of Web-Based Design In a Web-based design, the Internet serves as the front end, or interface for the database management system. Internet technology provides enormous power and flexibility In internet the system is not tied to any specific combination of hardware and software Access to the database require only a Web browser and an Internet connection Web-based systems are popular because they offer ease of access, cost-effectiveness, and worldwide connectivity Avicenna System Analysis and Design System Design

Web-Based Database Design Web-based design characteristics [1] Avicenna System Analysis and Design System Design

Web-Based Database Design Internet Terminology Web browser: An application that enables the user to navigate, or browse the Internet and display Web pages on his or her local computer. Web page: Text and multimedia documents that are found on the World Wide Web. HTML – Hypertext Markup Language: Is the language used to write Web pages for the Internet. Web server: A computer that is used to store and house Web sites. Web site: A collection of related Web pages. Intranet: A private, company-owned network that provides Web-based access to internal users Avicenna System Analysis and Design System Design

Web-Based Database Design Internet Terminology Extranet: An extension of a company intranet that allows access by external users, such as customers and suppliers. Protocols: A set of standards that govern network data transmission. Also, preset conditions used by firewalls to determine whether or not to allow traffic to pass. Web-centric: A strategy or approach that emphasizes a high degree of integration with other Web-based components. A Web-centric architecture follows Internet design protocols and enables a company to integrate the new application into its e-commerce strategy. Clients: Workstations that users interact with in a client/server design. These workstations, or computers, are supplied data, processing services, or other support from other computers, called servers. Servers: Computers in a client/server design that supply data, processing, and services to the client workstations. Avicenna System Analysis and Design System Design

Web-Based Database Design Connecting a Database to the Web Database must be connected to the Internet or intranet The database and Internet speak two different languages Database are created and managed using various programming languages and commands that have nothing to do with HTML To bridge the gab, it is necessary to use middleware Middleware: is software that connects dissimilar applications and enables them to communicate and exchange data. For example, middleware can link a departmental database to a Web server that can be accessed by client computers via the Internet or a company intranet. Avicenna System Analysis and Design System Design

Web-Based Database Design When a client workstation requests a Web page (1), the Web server uses middleware to generate a data query to the database server (2). The database server responds (3) and middleware translates the retrieved data into an HTML page that can be sent by the Web server and displayed by the user's browser (4). [1] Avicenna System Analysis and Design System Design

Web-Based Database Design Data Security Web-based data must be totally secure, yet easily accessible to authorized users To achieve this goal, well-designed systems provide security at three levels: the database itself, the Web server, and the telecommunication links that connect the components of the system Avicenna System Analysis and Design System Design

System Analysis and Design System Design Sequence Summary DBMS components include interfaces for users, database administrators, and related systems; data manipulation language; a schema; and physical data repository The physical repository might be centralized, or distributed at several locations In a Web-based design, the Internet serves as the front end, or interface for the database management system. Internet terminology include, web browser, web page, web server, web site, HTML, intranet, extranet, protocols, web-centric, clients, and servers When connecting database to the Internet they speak two different languages you need To bridge the gab, it is necessary to use middleware Middleware: is software that connects dissimilar applications and enables them to communicate and exchange data Avicenna System Analysis and Design System Design

System Analysis and Design System Design Sequence Summary In this Sequence we have Described the components of a database management system (DBMS) Described Web-based data design, including characteristics of Web-Based Design, Internet terminology, connecting a Database to the Web, and data Security Avicenna System Analysis and Design System Design

System Analysis and Design System Design Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt Publisher: SHELLY CASHMAN SEWIES. Avicenna System Analysis and Design System Design