Your “Unique Number” needs to be sequential? Be aware that sequential numbering is not supported by default on AppSheet and even if you use workarounds you can’t control the fact that two rows could end up using the same number.
Basically correct, although I don’t know how unique the last part could be and since we are talking about the key column we can’t correct it if there are two rows with the same “unique” number.
This is one of the best explanations about why sequential (which is the ideal setup IMHO for “unique numbers”) is not supported:
In general, sequential numeric identifiers (i.e., serial numbers) are risky in AppSheet: if two users happen to add rows at the same time, both rows could be assigned the same serial number, which could lead to confusion (at the least) or data loss (at the worst). For this reason, serial numbers are strongly discouraged!
[/quote]### ^ Some explicit and direct reference from the same post ^
In any case, @Saraappsheet haven’t confirmed that he needs sequential, although the problem is the same