Prevent duplicate value without set the column as key

[ckng6218]

Im looking for a way to prevent duplicate input without set the column as key column, was try with this formula at valid if feature and it's only work for new input, but when i want to edit then it will blocking me to save.

NOT(IN([_THIS],/*This Column*/))

Any one have idea how to build up a formula that can prevent duplicate input and still able to edit after this?

[TeeSee1 · Accepted solution]

One possible expression

ISBLANK(
 FILTER(
  "table",
  [this col] = [_THIS]
 )
 -
 LIST([_THISROW])
)

[yeyou4760]

i have a question will this work in my case 

Example: 1: box 52  Initial Stock: 5    |    2: box 105   Initial Stock: 55

i have multiple box locations with the same product barcode 

i would like the app to show each location and quantity 

the issue im having is that the each duplicate named barcode has the same box number 

https://drive.google.com/file/d/1Ae1oZSHbfsC8CbOIIFtJGb5IlYe7NhEP/view?usp=share_link

https://drive.google.com/file/d/1QTPBfBhHx9X-0UH0YxwozKUkg0mUu8yv/view?usp=share_link

[TeeSee1]

 I am not sure what you are asking...

Here your app already shows two separate entries for the same product (I suppose the 3 & 5 are initial stocks at different box locations..)

[ckng6218]

Great combination logic, thanks!