How to check country short form

Question

I am having these two table's

Country Table                                   Details Table
Id    CountryId      CountryName          Id   CountryId      Description
--------------------------------------          ----------------------------------
1           1                  UK                     1          1              xxxxx
2           2                  USA                   2          2             YYYYY
 
Design Page


i will collect country name and description and save details to database

My Problem
if user give the country name as United Kingdom and give description and click save..
@the time i my database i will use it as UK But user enter as United Kingdom occurs mismatch
if User enter as full formed country_name how to i identify the short form of that particular country.

For example:if user enter United Kingdom convert to UK
How do i will check it..

i am looking on this => is there any online website to do this?
Please Say any Idea.
~Thanks.