Please do not start by asking people to navigate to another site in order to
help you.  You need to describe your database's function, briefly describe
the tables, and identify key fields.  You don't need to list all of the
fields in every table, only the relevant ones.  "Employee personal
information" is all that is needed to describe an employee table, unless
particular fields are part of your question.  As for your question, a foreign
key exists because of its relationship to a primary key.  Without that
relationship it is just a field.  Are the foreign keys in question both
related to the same table, or to different tables?  What do you hope to gain
by relating them to each other?