Erik,

>>Yep this is a drawback, however I don't like the 128 bit (16 bytes) PK value either. It consumes too much memory.

>Is this really a practical concern? In what situation would this be a problem?

In nadya's case this is certainly a practical problem. If your table is growing towards 2GIG you certainly don't want a (n extra) PK of 16 bytes.

If for example I have a linking table with 3 foreign keys, which combined form a unique (PK) key, you can implement it in the folowing ways

1. a table that consist of three integer fields: 13 bytes record lenght
2. a table that consist of three 16 bytes character fields 49: bytes record lenght.
3 a table that consist of three 16 bytes character fields + 16 byte PK: 65 bytes record lenght.

The difference between 1 and 3 is 500%. This not only means that table 1 can contain 5 times more records than table 3, but also that performance is seriously affected because of larger indexkeys (because of the nature of the 128 bit key: it can not be compressed much, if at all). Rushmore actions require lots more of memory etc..

Walter,