A pair of matching columns is required to create a relationship.

You must select matching columns from both tables participating in a foreign key relationship. The columns you have selected don't match, so they cannot be related.

Choose two columns that match, and then attempt to establish the relationship. In order to match, there must be the same number of columns and each partner in a pair of columns must have a comparable data type.

For more information, see Foreign Key and Creating a Relationship Between Tables.