Comment by rdiddly

What's it called when the primary key is also a "foreign" (but not really) key into the same table? Anyway just do that. Each Item has a "PrecededByItemId" value. To insert X between A & B, just make X preceded by A and B preceded by X. Or probably better, go the other way (FollowedByItemId). It's the SQL version of a linked list. Efficient? Yes they're integers and an insert takes only two changes. Robust? Yes, infinite inserts possible. Elegant? Beats any of that complicated stuff in the article, unless I'm missing something. I suppose you could run out of integers but if your to-do list is that long, well...