ASP.NET MVC - Prevent duplicate field in EXCEL data upload

I have this Model Class

public COUNTRIES()

{

public int COUNTRY_ID { get; set; }

public string COUNTRY_CODE { get; set; }

public string COUNTRY_NAME { get; set; }

}

 

 

 

 

 

I want to perform batch upload of data from Excel with all the fields above and save into the database. I want the code to use the field COUNTRY_CODE as the UniqueIdentifier.

It will iterate through the Excel Sheet to check if COUNTRY_CODE exists in the database.

Please how do I go about it.

The code I have written will only upload and save, but will not treat duplicates.