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n You want assurance that each record in the table is accurate, thus the information
extracted from the table is accurate.
n You do not want to make the table (and its records) any larger than necessary.
The ability to assign a single, unique value to each record makes the table clean and reliable. This
is known as entity integrity. By having a different primary key value in each record (such as the
ContactID in the tblContacts table), you can tell two records (in this case, customers) apart,
even if all other fields in the records are the same. This is important because you can easily have
two individual customers with a common name, such as Fred Smith, in your table.
Theoretically, you could use the customer name and the customer??™s address, but two people named
Fred D. Smith could live in the same town and state, or a father and son (Fred David Smith and
Fred Daniel Smith) could live at the same address. The goal of setting primary keys is to create
individual records in a table that guarantees uniqueness.


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