Learn how to add and remove Primary Keys from an Access database table. The primary key's purpose is to promptly associate data from multiple tables and combine that data.

It links one table to a single record in another table; Primary Keys links tables. One- to- One Relationship can connect a table with many fields together and separate a table for security reasons.

The Unique Key column is set for the primary key of the CompanyCategory table (CompanyCatID). What that means is that when you delete a record, you will only delete one record at a time.