Block users from editing cells after the cell data is initially inputed?

is this possible? For example, I’d like to allow an employee/grist user to enter data in a cell, but once they enter it, they will not be able to edit it again after that.

can’t you set it to Create, but no Update on that column ?

I can only see R (read) and U (update), I don’t have a C (for create). Ive attached photo.
Oddly enough, that top user, it allows me to enter input in column CODE, but for another column like PRODUCT, it is blocked. Makes no sense to me since both have same settings. I’d basically love ALL users to enter input the first time, but then not be able to edit it afterwards. I guess I’d need the C function for create. Allow Create and then block Update. How can I get a C icon there as a permission?

I just tested a little more. So the first time I enter any input in a new row, it will allow any of the columns in that row to be inputed with data. Doesn’t matter which column. After that row has data in it, I can’t input data in any other column in that row.

set it for the table, not a specific column. If you enter a value in a column for the first time, isn’t that you are creating a row? So you set the table to C, no U.