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Introduction to Database Management. Chapter 1. Instructional Objectives. Importance of database design Premier Products Case Review of terms and concepts Advantages and disadvantages of database processing Processing of the past Database processing today Database systems, elements
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Introduction to Database Management Chapter 1
Instructional Objectives • Importance of database design • Premier Products Case • Review of terms and concepts • Advantages and disadvantages of database processing • Processing of the past • Database processing today • Database systems, elements • Database development
Importance of database design • Well-designed database facilitates data management and becomes a valuable information generator • A poorly designed database is a breeding ground for uncontrolled data redundancy • A poorly designed database generates errors that lead to bad decisions
In-class activity • Group Activity: using the order forms provided, determine the data the company must store and the data that is calculated. • Database use in the workplace • Example and purpose
Premier Products • Distributor of appliances, housewares, and sporting goods • Uses a spreadsheet to maintain its data • Problems: • Each item in an order has to be listed separately causing redundancy • Difficult to access data • Spreadsheets have limited security features • Size limitation of spreadsheets
Premier Products Order Form • Four entities: • Sales Rep • Part • Order • Customer
Terms and Concepts • Database – can store information about multiple entities, their attributes and relationships • Entity – person, place, object or event for which data is collected, stored or processed • Attribute – property of an entity (field or column) • Characteristics that describe an entity • Relationship – association between entities (1:1, 1:M, M:N) • DBMS – software that is used to interact with a database • ERD – visual representation of a database
Database Background (continued) FIGURE 1-7: E-R diagram for the Premiere Products database
Your turn… • What attributes would you use to describe yourself in: • a database of students? • a database of employees? • What happens when the data that is stored about you is incorrect? • List the attributes for the following object: • Coffee mug • Pen • Book
Advantages of database processing • Able to obtain more information with same amount of data • Able to Share data • Able to balance conflicting requirements • Able to control redundancy • Able to facilitate consistency • Able to improve integrity • Able to expand security • Able to increase productivity • Able to provide data independence
Disadvantages of database processing • Larger file sizes (disk space and memory) • Increased complexity • Due to complexity and breadth of functions provided • Greater impact of failure (for multiple users sharing same database) • More difficult recovery • Due to complexity of recovery process
Your turn… • One of the disadvantages of database processing is the greater impact of failure. If the student database or the course management system (for example, Blackboard) at your university is unavailable, how does that affect you? How does it affect your instructors?
Processing of the past • Used flat files (i.e. file processing systems) • Disadvantages: • Uncontrolled redundancy • Inconsistent data; Separate and isolated data • Inflexibility; Limited data sharing • Excessive program maintenance • Program-data dependence • Poor enforcement of standards (or integrity rules)
Database processing • Overcomes problems associated with file processing systems • Emphasizes integration and sharing of data across the organization • Advantages: • minimizes data redundancy • Sharing of data • Data independence • Reduced program maintenance
Database systems • Emphasize integration and sharing of data across the organization • By establishing relationships • Logically related data is stored in a single data repository
Elements of a Database System • Users • Database Application or program • DBMS – Access, Oracle, DB2, SQL Server, MySQL • Database SQL Database application DBMS user database
Database development • Begins with analysis of requirements • Followed by design • And finally, implementation Database design determines the structure of a database