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D I T211 Chapter 1 1
- 1. Chapter 1 Introduction to Database
- 2. Objectives At the end of this chapter, students should be able to: Identify the structure of database . Define data and information . Identify the hierarchy of data . Identify the types of data Identify the database . Identify the file based approach and database system approach Identify why we need database . Identify the purpose of database . Identify the components of database system . Evolution of database systems .
- 3. Database Structure Data Data consists of facts, text, graphics and figure that can be recorded and have implicit meaning. Information Information is the data that have been processed and being made to be useful for users or decision-makers.
- 4. Database Structure (cont.) Hierarchical Data Types of Data Text Numeric Boolean Currency Date / Time
- 5. Fundamentals of Database Non – Computerized System Non-computerized systems basically are all records or data that store manually in different file locations. The non computerized systems include telephone books, dictionaries, recipe books, encyclopedias and anything else which has organized and collected data. To make the data useful, additional information is designed based on the data to solve a problem with a purpose. Usually, a data is organized and sorted alphabetically, numerically, extracted or combined with other data to produce the useful information. Problem : Non-computerized System is not efficient because it consumes a lot of time to find and modify the information.
- 6. Fundamentals of Database (cont.) Traditional File Processing Approach All data are stored in individual files and each file has their own application program that manages and responsible their own files. Collection of application programs that provide services to end user such as producing report.
- 7. Fundamentals of Database (cont.) Disadvantages of File Based Approach Duplication of Data Same data is held by different programs and stored in several locations. This situation requires additional space and maintaining and updating data in several locations is expensive. Data Integrity Problem Files are stored within each application program that accesses a given data. The problem occurs if updates are not applied in every file. Changing the data in only one of the system will cause inconsistent data and result in the other system because of duplication of data. Limited Data Sharing Each application has it owns private files and users have little opportunity to share data outside their own application. Lengthy Development Time Each new application requires that the developer essentially start from scratch by designing new file formats. It takes time to manipulate the data.
- 8. Fundamentals of Database (cont.) Database Approach Definition of Database Database is a collection of related data, designed to meet the information needed in an organization and stores it in one specific location. Definition of Database Management System (DBMS) DBMS is a collection of programs that enable users to create and maintain a database and provide control access to the database. Definition of Application Program It is a custom developed program for processing a database. It can be written in a standard procedural language such as COBOL, C, or BASIC or in a language unique to the DBMS. Definition of Application It is a business computer system that processes a portion of the database to meet user information needs. It consists of menus, forms, reports, queries and application programs. Definition of User It is the person who uses, adds, deletes or modifies data in the database.
- 9. Fundamentals of Database (cont.) Figure 1-8 Database Management System
- 10. Fundamentals of Database (cont.) Why do we need database? For business use For personal use Purpose of Using Database To store information To find information Analyze and print information
- 11. Components of Database System Environment
- 12. Components of Database System Environment (cont.)
- 13. Components of Database System
- 14. Components of Database System (cont.) Database Collection of related data designed to meet user requirements / organization needs and stores in specific location. Elements of database User data Data that contains in a table / relations Metadata Structure of data that stores in data dictionary. Data dictionary stores the description of all objects that interact in the database. Index Data that are sort in ascending or descending order in the database, to improve the performance and accessibility of the database. Application metadata Used to store the structure and format of forms, reports, queries and other application programs created by user.
- 15. Components of Database System (cont.)
- 16. Components of Database System (cont.)
- 17. Components of Database System (cont.)
- 18. Components of Database System (cont.) DBMS Engine Intermediary between design tools and run time. Design tools A design tool has a set of tools to design and create the database application. It includes tools for creating tables, forms, queries and reports. Run time Processes the application components that are developed by using design tools.
- 19. Components of Database System (cont.) Table Stores information about specific topic.
- 20. Components of Database System (cont.) Forms Display information inside the database in an attractive way. Provide the fastest way to view, enter and modify data in a database.
- 21. Components of Database System (cont.) Queries Allows user to find information needed from the database.
- 22. Components of Database System (cont.) Reports Documents that contains summarized data in a database.
- 23. Advantages of Database Approach Minimal Data Redundancy – because data is stored in a single database, data item do not need to be duplicated in separate files for various systems. Sharing of data – data can be shared across the enterprise, allowing more users to access more data. Economy in distributing database – database design allows better utilization of hardware. For example, company does not need to use expensive mainframe but using distributed databases on smaller computers. Improved Data Consistency – by eliminating data redundancy, the data inconsistency also reduced. For example, if a customer address is stored only once, we cannot have disagreement on the stored values. Updating values is greatly simplified when each value is stored in one place only.