Multiple Primary Keys

[JonathanOz]

This is kind of rudimentary, but I'll ask it anyway. I have a table where each record is unique if at least one of three variables is different. The three variables in my case are each integers and are:

1. Year
2. Route
3. Segment.

Now each of these individual variables allows (and has) duplicates, but if the thing is working right, no pair of records in this table should have all three of these variables with identical values. Is this table a candidate for using multiple primary keys?

[orange]

Read through this tutorial for background on table design, normalization and Primary Key.

http://www.rogersaccesslibrary.com/T...lationship.zip

[John_G]

Hi -

My opinion: you would not have multiple primary keys (a table can have only one PK), but your primary key would be a compound key consisting of the three fields. Nothing wrong with that; it will prevent duplication, which is what you want to do. Just be aware that things might get a bit complicated if you want to use that table in relationships using that PK. Will you be doing so?

John