Constraint question - maybe simple?

I have a table TRAIN with several fields, and the three ones of importance are:

1. TRAIN_I number not null
2. P_VERSION_I number not null
3. TRN_SYMBOL_I varchar2(6) not null

The primary key is on TRAIN_I and P_VERSION_I.

Is it possible to add a constraint such that there can be several pairs of (TRAIN_I, TRN_SYMBOL_I) but they must match? What I mean is, if there is one record with TRAIN_I = 123, and TRN_SYMBOL_I = ABC, and we add another record with TRAIN_I = 123 (and a different P_VERSION_I of course), then it is constrained to have TRN_SYMBOL_I = ABC?

I can't think of a simple way, although I am a beginner here.

Thanks,

Dean Received on Mon Oct 24 2005 - 10:59:11 CDT