Inserting Records...

Ok, I know this is already part of another thread, but my problem is a bit more complex...

The database I've been designing catalogs traffic signal equipment at every intersection in a 12-county area. There's about 480 intersections in the database. My boss pointed out the need to have the intersections listed in geographic order. For example, if I have three intersections on IL Rte. 5 - John Deere Rd, Bauer Parkway, and Industrial Park Rd, they need to be listed in the order in which they exist on the road (from east to west or north to south). Alphabetically, the intersections would be Bauer, Industrial, John Deere. But, as you drive down the road (from east to west), the intersections occur as Industrial, Bauer, and John Deere.

I can sort the intersections according to their "corridors" without any trouble, but I have to force the geographic order of the individual intersections by assigning each an index value (like "1", "2", and "3"). Better yet, I can assign the indices in multiples of 10, 100 or 1000, (1,2,3 becomes 10,20,30 or 100, 200, 300, etc.) and guarantee there will likely always be a sequential position available in the geographic index for a new intersection. Plus, I can always pick the "middle" of the range for each new insertion. For example, if Bauer has a geographic index of 200 and John Deere's is 300, then I can give Zebulon a value of 250 - leaving equal room for insertions before and after Zebulon in the future.

Pulling this off isn't hard - I know how to do it. The problem is running out of positions in the index. In the case of my database, it is unlikely we'll ever add more than two or three intersections between two existing ones, so using multiples 100 is probably best. In this case, I can add at least 6 intersections before I run into the possibility of having two intersections whose indices have a difference of only 1. Using 1000, the value goes up to 9. Each multiple of ten gives you 3 more entries (minimum) before encountering consecutive indices. I guess the inherent problem is figuring out a more "infinite" way of accomplishing this. I don't readily need it, but on the off chance that I do end up with consecutive intersections (that I have to insert between), it'll require manual re-numbering to fix the problem.

That's my solution, but there may be something simpler. Any thoughts?