Foreign key

Dear Sarah

Thank you for attending Access Introduction course!! I hope you enjoyed the course and benefited from it.


Mark has kindly provided a detailed explanation for which I would like to thank Mark.

More practical approach to primary and foreign keys is explained in Intermediate level where we see Three rules of Normalisation and then also look as diffrent types of relationships that can exist between two or more tables!!

In brief Primary key is a unique identifier for a record so no two records can have the same data in the field that is set to primary key.

In order to link the two tables you may have the field with the same name in the other table but not as a Primary key but as a foreign key.

I hope this can be clear from the example below:

One department can have many employees but one Employee can only be in one dept at one time. So there should be One-to-many relationship between the two tables called Employees and Department.

Employee table will have a primary key called Employeed ID
Department table will have a primary key called Department Code.

But in Employee table you will also have the Department code to specify which employee is in what dept. So the dept. code in the Employees table will be the foriegn key.

If you are familiar with the process of establishing relationship then you may know that in the relationships window you'll drag the Primary key in the departmens table and drop it on the foreign key of the Employees Table i.e. department code (primary key) in the department table to the Deartment code (foreign Key) in the employeses table.

I hope this has answered your query.

If this has answered your query then I would request you to please mark the question as resolved!! If not and you have a specific question related to this then please post it as a new question and we should be able to provide you the solution for it!!

Kindest Regards


Rajeev Rawat
MOS Master Instructor 2000 and 2003
MCAS Master Instructor 2007