How can I validate a drop down list? I have a "Material Requested" column and a "Issued" or "Returned" column. If a item gets requested we choose issued. I want to make sure the Item is returned before it get issued again. Basically, I want to enforce unique values on the "Material Requested" Column
That means, you want a “Material Requested” to be able to be issued only after it is returned.
You can enforce unique values for “Material Requested” column. This feature prevents users from duplicating data.
If user wants to issue/return the existing “Material Requested”, he can only edit the item and modify "Issued/Returned" column to set the status. So that, user cannot issue “Material Requested” again before it get returned.