I think imposing order into numerical ° IDs works only for static structures.

If the max depth is fixed I can easily create a performant view where each column represents a level.

SQL views on self joins are even updatetable in mysql.

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Of course there are attempts to use a path like strings as ID, ie 0_1 would be a parent of 0_1_15 , but this becomes a can of worms if you need to move branches ...

°) integers to be more precise