Hi, hopefully someone can help me with this. I'm currently working on a data model for a database-design assignment for university. I have to label up my model accurately including all the labels and keys, ie using boxes to represent tables and lines between showing relationships and their cardinality.

1. I have unique columns for each of my tables called Primary Keys,

2. I have columns from other tables called Foreign Keys,

3. But I also have a column which is the Primary Key of a particular table, but it is from another table and so is Foreign... Can anyone tell me the name of this key? and how are they usually marked up or flagged as being both on a model?

You can have a key that is both primary and foreign

(PK) Primary Key

(FK) Foreign Key

(PK, FK) Primary Key and Foreign Key.

Sometimes called a Foreign Primary Key.

That should do it.

thanks for your quick response,

so there is no unique name for a key which is both primary and foreign??!

I wasn't sure if it was called composite or compound but think that is something else.

A foreign primary key.

(slipped in previous post while adding key's name)

You have two tables with a 1 to 1 relationship?

blindman