TAILIEUCHUNG - Lecture Information systems (3e): App C - Paige Baltzan

After completing this unit, you should be able to: Discuss the role of planning in the business use of information technology, using the scenario approach and planning for competitive advantage as examples; discuss the role of planning and business models in the development of business/IT strategies, architectures, and applications; identify several change management solutions for end user resistance to the implementation of new IT-based business strategies and applications. | APPENDIX C DESIGNING DATABASES Copyright © 2015 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education. 1 INTRODUCTION The core chapters introduced: Database - maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses) Database management system (DBMS) – creates, reads, updates, and deletes data in a database while controlling access and security Relational database model - a type of database that stores its information in the form of logically-related two-dimensional tables 2 ENTITIES AND DATA RELATIONSHIPS Data model – The logical data structures that detail the relationships among data elements using graphics or pictures The underlying relationships in a database environment are: Independent of the data model Independent of the DBMS that is being used Entity-relationship diagram (ERD) - A technique for documenting the relationships between entities in a database environment 3 Entities And Their Attributes Entity - Also called a table, stores information about a person, place, thing, transaction, or event A customer is an entity, as is a merchandise item Attribute – Data elements associated with an entity A CUSTOMER entity can be described by a Customer Number, First Name, Last Name, Street, City, State, Zip Code, Phone Number 4 Entities And Their Attributes 5 Attributes There are several types of attributes including: Simple versus composite Single-valued versus multi-valued Stored versus derived Null-valued 6 Simple versus Composite Composite attributes can be divided into smaller subparts, which represent more basic attributes that have their own meanings Example: Address Address can be broken down into a number of subparts, such as Street, City, State, Zip Code Street may be further broken down by Number, Street Name, and Apartment/Unit Number Attributes that are not divisible into subparts are called simple

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