Establishing Each Relationship
This process involves defining an explicit logical connection between a pair of related tables. The type of relationship that exists between the tables determines the manner in which you define the connection.
One-to-One and One-to-Many Relationships
You use a primary key and a foreign key to establish the connection between tables participating in a one-to-one or one-to-many relationship. (You'll learn the definition of a foreign key in just a moment.)
The One-to-One Relationship
In this type of relationship, one table serves as a parent table and the other serves as a child table. A record must exist in the parent table before you can enter a related record in the child table; stated another way, ...