Detect in the system

[H]

Hi 

i would like some help

i created a manufacturers database, each ingredients has a unique 10 letter/number code.

i want that if the code is already in the system it should tell the user the ingredients is already in the system, i don`t want it to replicate.

please can someone help me script this to detect that.

[webko]

You can do this with field level validation, so that entries must be unique

[Kris M]

+1 webko

this is a data layer problem and the fix should be the same.