CHAPTER 1: THE DATABASE ENVIRONMENT

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1 CHAPTER 1: THE DATABASE ENVIRONMENT DATABASE An organized collection of logically related data. A database may be of any size and complexity. o by organized, data are well structured so as to be easily stored, manipulated & retrieved by users. o by related, data describe a domain of interest to a group of users and that the user can use the data to answer questions concerning that domain. DATA referred to known facts that could be recorded on a computer media. Facts, text, graphics, images, sound and video segments that have meaning in the users environment. o Structured: numbers, text, dates o Unstructured: images, video, documents THE DATA PROCESSING CYCLE In computing, data pertains to a raw aggregate of facts, which when subjected to processing become meaningful. This processed data is referred to as information. Information is organized data and presented in a manner that has additional meaning and value beyond the data itself. Typically, this data conversion is termed IPO which stands for input-process-output. Initially, data is fed as input for processing (1) and information is produced (2) as the output. Processed data may be saved or stored in a storage media such as a hard disk (3), and retrieved back for future or later use as an input for succeeding operations (4). This means then that input may either be data or information. In all cases, however, outputs of processing are referred to as information. During processing, some old data stored previously may be needed to complement or complete the operation at hand (5) and processed results may be written back to update the old data (6). INFORMATION Data that have been processed in such a way as to increase knowledge of the person who uses the data. METADATA data that describes the properties and context of user data. Figure 2. Data in Context Context helps users understand data Figure 2. Summarized Data Graphical displays turn data into useful information that managers can use for decision making and interpretation Page 1

2 Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and data context DISADVANTAGES OF FILE PROCESSING SYSTEM 1. Program-Data Dependence o All programs maintain metadata for each file they use 2. Duplication of Data o Different systems/programs have separate copies of the same data 3. Limited Data Sharing o No centralized control of data 4. Lengthy Development Times o Programmers must design their own file formats 5. Excessive Program Maintenance o 80% of information systems budget Problems with Data Dependency Each application programmer must maintain his/her own data Each application program needs to include code for the metadata of each file Each application program must have its own processing routines for reading, inserting, updating, and deleting data Lack of coordination and central control Problems with Data Redundancy Waste of space to have duplicate data Causes more maintenance headaches The biggest problem: o Data changes in one file could cause inconsistencies o Compromises in data integrity SOLUTION: The DATABASE Approach Central repository of shared data Data is managed by a controlling agent Stored in a standardized, convenient form Requires a Database Management System (DBMS) Page 2

3 DATABASE MANAGEMENT SYSTEM A software system that is used to create, maintain, and provide controlled access to user databases DBMS manages data resources like an operating system manages hardware resources ADVANTAGES OF THE DATABASE APPROACH 1. Program-data independence 2. Minimal data redundancy 3. Improved data consistency 4. Improved data sharing 5. Increased productivity & application development 6. Enforcement of standards 7. Improved data quality 8. Improved data accessibility and responsive/ness 9. Reduced program maintenance Costs and Risks of the Database Approach 1. New, specialized personnel 2. Installation and management cost and complexity 3. Conversion costs 4. Need for explicit backup and recovery 5. Organizational conflict Relational Databases Database technology involving tables (relations) representing entities and primary/foreign keys representing relationships Database Applications Application programs that is used to perform database activities for database users. o Create: Add new data to the database o Read: Read current database data o Update: Modify current database data o Delete: Remove current data from the database. RANGE OF DATABASE APPLICATION 1. Personal Database (1) Designed to support one user. Personal databases have long resided on personal computers (PC s), including laptops. Page 3

4 2. Workgroup Database (5-25) Designed to support the collaborative efforts of such team. Workgroup relatively small team of people who collaborate on the same project or application. Database Server central storage device, connected to the network Figure 3. Workgroup database with wireless 3. Department Database (25-100) Designed to support various functional and activities on a department Department a functional unit within an organization. 4. Enterprise Database (>100) One whose scope is the entire organization or enterprise. ERP(Enterprise Resource Planning) are software applications that provide the data necessary for the enterprise to examine and manage its activities. Data Warehouse an integrated decision support whose content is derived from the various operational database. Figure 4 An enterprise data warehouse Page 4

5 5. Web enabled (>1000) INTERNET Worldwide network that connects users of multiple platforms easily. INTRANET Use of internet protocol to establish access to company data and information that is limited to organization. EXTRANET Use of internet protocol to establish access to company data and information by the company s customers & suppliers. COMPONENTS OF THE DATABASE ENVIRONMENT 1. CASE (Computer-Aided Software Engineering)Tools An automated tools use to design databases and application program. System developers often use this tools for system requirements analysis and program design. 2. Repository Centralized knowledge base for all data definitions, data relationships, report formats, and other system components. 3. Database Management System (DBMS) Commercial software system used to define, create, maintain, and provide controlled access to the database and repository. 4. Database An organized collection of logically related data, usually designed to meet the information needs of multiple users in an organization. 5. Application Programs Are used to create and maintain the database and provide information to users. 6. User Interface text and graphical displays by which users interact with various system components, such as CASE tools, application programs, the DBMS & repository. 7. Data/Database Administrators personnel responsible for maintaining the database 8. System Developers personnel responsible for designing databases and software 9. End Users people who uses the applications and databases. Page 5