1. McGraw-Hill/Irwin © 2008 The McGraw-Hill Companies, All Rights Reserved Chapter 7 Storing Organizational Information - Databases

2. 7-2 Learning Outcomes 7.1 Define the fundamental concepts of the relational database model 7.2 Evaluate the advantages of the relational database model 7.3 Compare relational integrity constraints and business-critical integrity constraints

3. 7-3 Learning Outcomes 7.4Describe the benefits of a data driven Web site 7.5 Describe the two primary methods for integrating information across multiple databases

4. 7-4 Relational Database Fundamentals Information is everywhere in an organization Information is stored in databases –Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

5. 7-5 What is the purpose of a database? Spreadsheet and database keep track of things Spreadsheets –Keep lists of single concept Databases –Keep lists that involve multiple themes

6. 7-6 Database Models Database models include: –Hierarchical database model – information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships –Network database model – a flexible way of representing objects and their relationships; each record may have multiple parents –Relational database model – stores information in the form of logically related two-dimensional tables

7. 7-7 Hierarchical database model A method for storing data in a database that looks like a family tree with one root and a number of branches or subdivisions. Instrumental Music X

8. 7-8 Network database model A database design for storing information by linking all records that are related with a list of pointers.

9. 7-9 Relational database model A design used in database systems in which relationships are created between one or more tables based on the idea that each pair of tables has a field in common.

10. 7-10 Relational Databases In the rest of this course we only focus of Relational Databases since they are far more applicable to businesses.

11. 7-11 Entities and Attributes Entity – a person, place, thing, transaction, or event about which information is stored –The rows in each table contain the entities Attributes (fields, columns) – characteristics or properties of an entity class –The columns in each table contain the attributes

12. 7-12 Keys and Relationships Primary keys and foreign keys identify the various entity classes (tables) in the database –Primary key – a field (or group of fields) that uniquely identifies a given entity in a table –Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables

13. 7-13 Keys and Relationships Potential relational database for Coca-Cola Primary Key Foreign Key Primary Key Foreign Key

14. 7-14 Another example of Relationships among tables

15. 7-15 Why Relational models What is wrong with putting all information in the previous slide all in ONE table?

16. 7-16 Relational Database Advantages Database advantages from a business perspective include –Increased flexibility –Increased scalability and performance –Reduced information redundancy –Increased information integrity (quality) –Increased information security

17. 7-17 Increased Flexibility A well-designed database should: –Handle changes quickly and easily –Provide users with different views –Have only one physical view Physical view – deals with the physical storage of information on a storage device such as hard drive –Have multiple logical views Logical view – focuses on how users logically access information

18. 7-18 Increased Scalability and Performance A database must scale to meet increased demand, while maintaining acceptable performance levels –Scalability – refers to how well a system can adapt to increased demands –Performance – measures how quickly a system performs a certain process or transaction

19. 7-19 Reduced Information Redundancy Databases reduce information redundancy –Redundancy – the duplication of information or storing the same information in multiple places Inconsistency is one of the primary problems with redundant information

20. 7-20 Increase Information Integrity (Quality) Information integrity – measures the quality of information Integrity constraint – rules that help ensure the quality of information –Relational integrity constraint –Business-critical integrity constraint

21. 7-21 Increased Information Security Information is an organizational asset and must be protected Databases offer several security features including: –Password – provides authentication of the user –Access level – determines who has access to the different types of information –Access control – determines types of user access, such as read-only access

22. 7-22 Databases, and then what ? It provides a framework to store large-scale networked data –Increased flexibility –Increased scalability and performance –Reduced information redundancy –Increased information integrity (quality) –Increased information security Ok, we got a database, so now how we can get (Organizational) Information?

23. 7-23 Database Management Systems Database management systems (DBMS) – software through which users and application programs interact with a database

24. 7-24 DATA-DRIVEN WEB SITES Data-driven Web sites – an interactive Web site kept constantly updated and relevant to the needs of its customers through the use of a database

25. 7-25 Data-Driven Web Site Business Advantages Development Content Management Future Expandability Minimizing Human Error Cutting Production and Update Costs More Efficient Improved Stability Developing DB  Website Interface Driven from the Database Easier, by extending the DB Driven from the Database Only requires DB updates Efficient Querying through DB Utilize the power of DB security and Scalability

26. 7-26 Data-Driven Business Intelligence BI in a data-driven Web site

27. 7-27 Integrating Information among Multiple Databases Integration – allows separate systems to communicate directly with each other –Forward integration – takes information entered into a given system and sends it automatically to all downstream systems and processes –Backward integration – takes information entered into a given system and sends it automatically to all upstream systems and processes

28. 7-28 Integrating Information among Multiple Databases Forward integration

29. 7-29 Integrating Information among Multiple Databases Backward integration

30. 7-30 Integrating Information among Multiple Databases Building a central repository specifically for integrated information