1. Exploring Microsoft Access 2003 Chapter 6 Many-to-Many Relationships: A More Complex System

2. Objectives Define and explain a many-to-many relationship Use cascade Update and Cascade Delete Explain how AutoNumber field simplifies entering new records (Autonumber is compatible with long integers) Create a main and subform based on a query Create a parameter query Use aggregate function Use Get External Data command

3. Overview More database design practice Extends relational database concepts Use AutoNumber to simplify record creation Extends subform and query information for related tables Create a parameter query Create queries with built-in aggregate function

4. Case Study: Computer Super Store A relational database with more than two tables Finding information becomes more difficult unless you use a database Many-to-many relationship implemented by a pair of one-to-many relationships

5. Case Study: Computer Super Store Combined keys necessary when a pair of one- to-many relationships is built into a separate table Using the AutoNumber field type keeps order Relationships window shows visual relationships Enforce referential integrity

6. Implementing Many-To-Many Relationships Enforce Referential Integrity is selected Many-to-many Relationship is implemented by a pair of one-to-man relationships

7. Relationships and Referential Integrity Hands-On Exercise 1 Add a Customer Create the Relationships Delete an Order Details Record Edit a Relationship Delete a Record in the Orders Table

8. Subforms, Queries, and AutoLookup Main and subforms based on queries: – display information from multiple tables – display records other than by primary key AutoLookup will find corresponding data after unique ID is entered

9. Main Form and Subform Main form has fields from Consultants table Subform has fields from Client table

10. Designing a main and subform Main form detail Subform detail

11. Subforms and Multiple Table Queries Hands-On Exercise 2 Create the Subform Query Test the Query Create and Modify the Orders Form Change the Column Widths Enter a New Order Print the Completed Order

12. Advanced Queries Parameter query prompts for criteria when executed Total queries performs calculations on a group of records Total row – Contains either Group by or aggregate entry Group by – Records in the dynaset are to be grouped according to the like values Sum Function – Specifies math to performed on that field for each group of records

13. Parameter Query Run button Table row indicates Table from which a field comes Enter prompt is square brackets

14. Advanced Queries Hands-On Exercise 3 Create the Query The Report Wizard Modify the Report Design Print the Report Copy an Existing Query Create and Run a Total Query Create a Parameter Query Exit Access

15. Expanding the Database Existing tables are unaffected by adding a fifth table Use parameter query to calculate data Use Get External Data command to import a table from another database

16. Adding Tables Existing tables and relationships are unaffected by addition of new tables

17. Expanding the Database Hands-On Exercise 4 Import the Salesperson Table Modify the Orders Table Design Add the Salesperson to Existing Orders Create a Relationship Modify the order with Customer Information Query Modify the Order Form The Completed Order Form Database Properties

18. Chapter 6 Summary (1 of 2) A many-to-many relationship requires an additional table Many-to-many is implemented with a pair of one-to- many relationships Enforce referential integrity to prevent errors Base forms and subforms on queries

19. Chapter 6 Summary (2 of 2) Parameter query uses prompts Aggregate functions perform calculations on groups of records New tables may be added at any time without affecting data in the existing tables

20. Practice with Access 1. Sales Commission 2. Find products that have never been ordered 3. Super Store Customer Form 4. Add Command Button to Order Form 5. Final Super Store Order Form 6. The Switchboard 7. The Startup Property

21. Case Studies Medical Research The Stock Broker The Video Store Class Scheduling Career Planning and Placement