1. Tables & Relationships
Quick Review-Steps when Creating a Database
Steps to complete before creating the database using the software
Decide what information you will store in the database
Create the layout of the database
Create a relationship diagram to identify the table relationships, primary keys and foreign keys
4. Create the database using the database software

2. Create the database using the database software
Create the Database File
Create the tables
Fields
Primary keys
Field Types
Field Properties
We know the information we want to store, but how do we match a customer’s name to their charges and payments?
We need a way to relate these two tables to extract useful information.
We can relate these two tables by matching the Client ID
We do this by “Joining” the tables
Create the Relationships

4. ∞ 1 Parent Child Table Name: Client Primary Key: ClientID Table Name:
Payments
Primary Key:
None
FK: ClientID On Payments table

5. Relationship Rules
Must be a primary key in least one of the tables in the relationship.
The related fields must be the same data type
number, text etc.
The foreign key field must contain the same information as the primary key field.
The field names on each table do not have to match as long as the information is the same.
FK: ClientID On
Payments table
Table Name: Client
Primary Key: ClientID
Table Name: Payments
Primary Key: None

6. Referential Data Integrity
A set of rules that specifies what records may exist in each table
A record input with a foreign key must always have a matching record in the primary key table in the relationship

7. Cascade Delete Related Records
Removing any entry in a primary key field will automatically remove all entries in foreign key fields of related tables.
Cascade Update Related Records
Updating any entry in a primary key field will automatically update all entries in foreign key fields of related tables.

8. ∞ ∞ ∞ 1 1 1 Parent Parent Child Child Child Parent Table Name: Client
FK: ClientID On Payments table
FK: ClientID On Charges table
Table Name:
Client
Primary Key:
ClientID
Parent
Parent 1 1
Child ∞
Child ∞
Table Name:
Payments
Primary Key:
None
Table Name:
Charges
Primary Key:
None ∞
Child
FK: PaymentType On Payments table 1
Parent
Table Name:
MethodTypes
Primary Key:
MethodID
A Foreign Key (FK) is a field that defines the relationship between 2 tables.