1. Microsoft Access Lesson 3
Lexington Technology Center
February 18, 2003
Bob Herring
On the Web at

2. Review of Thursday’s Lesson
Access Lesson 3
Review of Thursday’s Lesson
Template Databases
Database Wizard
Switchboard Forms
Forms and Controls
Reports
Database Window 2

3. Access Lesson 3 Relationships
Tables can be related if they have a field in common. Access uses the
relationship to create information by matching the fields and reporting the
results.
There are 3 types of relationships:
One-to-many: Each record in the primary table can be associated with
many records in the related table
One-to-one: Each record in the primary table can be associated with
only one record in the related table
Many-to-many: More than one record in the primary table can be
associated with many records in the related table 3

4. Relationships in Access
Access Lesson 3
Relationships in Access
The table on the “one” side of the relationship is called the parent table.
The other table is called the child table.
How the 3 types of relationships are created in Access:
One-to-many: The common field in the parent table is called the
primary key, and the related field in the child table is
called the foreign key.
One-to-one: The common fields are both primary keys.
Many-to-many: Ordinarily not possible, but in Access two one-to-
many relationships can be joined to create this kind
of relationship. 4

5. One-to-Many Relationships
Access Lesson 3
One-to-Many Relationships
In this example, one category can encompass many products
Child
Table
Foreign
Key
Parent
Table
Primary
Key
Relationship Line 5

6. One-to-One Relationships
Access Lesson 3
One-to-One Relationships
These two tables have a one-to-one relationship because they
concern the same subject: employees 6

7. Many-to-Many Relationships
Access Lesson 3
Many-to-Many Relationships
Since many orders might call for many products, a junction table
is used to avoid violating referential integrity.
Junction
Table 7

8. Referential Integrity
Access Lesson 3
Referential Integrity
Optional series of rules that guarantees that relationships will be valid.
Every record in a child table (the “many” side) must have one and
only one record in the parent table (the “one” side)
No child record can be entered without a parent
No parent record can be deleted if it still has children
No child record’s foreign key can be changed without a match in
the parent table
No parent table’s primary key can be changed if there are child
records 8

9. Referential Integrity, Continued
Access Lesson 3
Referential Integrity, Continued
What you need to enforce referential integrity in Access:
The matching field in the parent table must be the primary key
Relating fields must be the same data type
Both tables must be in the same database -- OR, if using linking
fields, both tables must be in Access and the linked table’s
database must be open
Referential integrity is indicated by 1 -  on the relationship line
Referential
Integrity
Enforced 9

10. Referential Integrity, Continued
Access Lesson 3
Referential Integrity, Continued
Referential integrity is set by editing the relationship
Right-click the relationship line and select Edit Relationship
Click the “Enforce Referential Integrity” check box
Enforce Referential Integrity
Edit Relationship 10

11. Referential Integrity, Continued
Access Lesson 3
Referential Integrity, Continued
If referential integrity is selected, you can also choose to have Access
automatically update or delete records
Cascade Update and Cascade Delete maintain referential integrity by
changing child tables to match changes in the parent table
Beware of Cascade Delete!! This could lead to loss of data!
Cascade Update has no effect if you are using a primary key since
you cannot change an autonumber
Cascade Update
Cascade Delete 11

12. Access Lesson 3
Joins
A join is a control that tells Access which records to select when
running a query.
Inner joins are the most common.
Outer joins include all records from one of the tables and records
from the other when the joined fields match.
Left
Right
Inner
Join
Left
Outer Join
Right
Outer Join 12

13. Address Book Relationships
Access Lesson 3
Address Book Relationships 13

14. Asset Tracking Relationships
Access Lesson 3
Asset Tracking Relationships 14

15. Contact Management Relationships
Access Lesson 3
Contact Management Relationships 15

16. Event Management Relationships
Access Lesson 3
Event Management Relationships 16

17. Expenses Relationships
Access Lesson 3
Expenses Relationships 17

18. Students and Classes Relationships
Access Lesson 3
Students and Classes Relationships 18

19. Inventory Control Relationships
Access Lesson 3
Inventory Control Relationships 19

20. Access Lesson 3
Ledger Relationships 20

21. Resource Scheduling Relationships
Access Lesson 3
Resource Scheduling Relationships 21

22. Time and Billing Relationships
Access Lesson 3
Time and Billing Relationships 22

23. Membership Relationships
Access Lesson 3
Membership Relationships 23

24. Order Entry Relationships
Access Lesson 3
Order Entry Relationships 24

25. Book Collection Relationships
Access Lesson 3
Book Collection Relationships 25

26. Music Collection Relationships
Access Lesson 3
Music Collection Relationships 26

27. Access Lesson 3 Form Wizard
In the Northwind database, select the “Forms” tab
Click the “New” button 27

28. Access Lesson 3 Form Wizard
In the “New Form” dialog box, click “Form Wizard”
Choose the Products table to begin, then click “OK” 28

29. Wizard, Step 2 -- Data Fields
Access Lesson 3
Wizard, Step 2 -- Data Fields
Step 2 is to choose fields from the available tables and queries
Click the right arrow to select the desired fields, or
Click the double right arrow to select all 29

30. Choosing Fields for a Form
Access Lesson 3
Choosing Fields for a Form
Select “ProductName”, “SupplierID”, “UnitsinStock”,
and “Discontinued”
Choose “Next” 30

31. Wizard, Step 3 -- Layout Style
Access Lesson 3
Wizard, Step 3 -- Layout Style
In Step 3, select a layout style for the form
Click through the four choices to preview the different styles
Click “Next”
Columnar
Tabular 31

32. Wizard, Step 3 -- Layout Style
Access Lesson 3
Wizard, Step 3 -- Layout Style
In Step 3, select a layout style for the form
Click through the four choices to preview the different styles
Click Next
Datasheet
Justified 32

33. Wizard, Step 4 -- Background Style
Access Lesson 3
Wizard, Step 4 -- Background Style
In Step 4, select a background style for the form
Click through the choices to preview the different styles 33

34. Access Lesson 3 Wizard, Step 5 -- Finish
To finish the form, give it a name and click “Finish”
Click the radio button to open the form after creating it
Open
the Form 34

35. Automatic Form in Action
Access Lesson 3
Automatic Form in Action
The new form displays a portion of the information in the table
Forms are two-way -- they display information, but also guide
data entry 35

36. Access Lesson 3 Adding a New Product Click the “New Record” button
Notice that the “Supplier” field is lit -- this is referential integrity
in action -- every product must have a supplier! 36

37. Access Lesson 3 Adding a New Product
After choosing a supplier, enter the name of the new product
Enter the number of units in stock
Data entered in the form is immediately saved in the database 37

38. Access Lesson 3 Review Relationships Referential Integrity Joins
Template Database Relationships
Automatic Forms 38