1. Advanced Accounting Information Systems Day 7 Database Modeling

2. Announcements –Career Services presentation today at 5:10 to 5:40 in Gerdin 2118 –Business Week starts on Sept 16 th –Assignment 1 Process map Document flowchart Systems flowchart Context data flow diagram Logical level 0 data flow diagram

3. Objectives Understand why databases are important in today’s environment Describe concepts of data hierarchy, record structures, and keys Describe how to use data dictionaries Describe why processing accuracy, concurrency, and security are important to multiuser databases Develop data models using REA Identify the key differences between logical view of information and physical view of information Identify the advantages of using a relational structure rather than either a hierarchical or network structure to organize database records

4. Questions for today Why are databases important to businesses?

5. Question for today What is the purpose of a primary key? What is the purpose of a secondary key?

6. Question for today What is the purpose of a data dictionary?

7. Question for today What is the purpose of a data model?

8. Storing Data in Databases Data hierarchy Two types of tables Record structure Foreign keys

9. Additional Database concerns Administration Documentation Data integrity controls –Data field type –Valid code test –Reasonableness tests Processing accuracy and completeness Concurrency controls Backup and security –View controls

10. Entity Relationship Diagrams Data model Entity Attribute Relationship Cardinality

11. Entity Relationship Diagrams Steps in Process of creating ERD Diagramming symbols –Chen –Bachman –Martin

12. Entity Relationship Diagrams Basic model for each transaction cycle

13. Resource Event Agent Data Model Special ERD to model accounting information systems Three ‘rules’ –Each event generally involves at least one resource –Each event generally involves two agents – one internal and one external –Each subsequent event should be shown below its prior event

14. Resource Event Agent Model Example Martin Shoes manufactures and distributes orthopedic footwear. To sale its products, the marketing department requires sales personnel to call on the shoe retailers within their assigned geographic territories. Each salesperson has a laptop computer, which he/she uses to record sale orders during the day and to send these sales orders to Martin’s network nightly for updating the company’s sales order file. Each day, warehouse personnel review the current sales orders in its file, and where possible, pick the goods and ready them for shipment. When the shipping department completes a shipment, it also notifies the billing department, which then prepares an invoice for the customer. Payment terms vary by customer, but most are net 30. When the billing department receives a payment, the billing clerk credits the customer’s account and records the case received.

15. Questions for Friday What is the purpose of a foreign key? What is referential integrity? Why is it important to store primary key values consistently within different tables of the same database? What are database cardinalities?