Create Primary Key after Bulk Insert

Hello,

I am building a bulk insert query in SQL 2012.  

Everything I want has been accomplished except for the item below:

When I run the bulk insert I need a way to

1.) create a primary key based on 2 of the columns in the flat file (I have attached this in an excel file as an example of how it looks).

2.) If I run the bulk insert query again I want the rows to fail that have the same primary key.  For example, if records have been imported with the DTAL_RRN = 48232604 and EXTERNAL_SN = 2085 already I would want these records to fail on import if someone tries to run the query again.  I used this example because it is the first line in the attached file.


The Bulk insert looks like this:

bulk insert DTAL_ALL

from

'c:\dtal_all\DTAL2085-1.csv'

with

(DATAFILETYPE = 'char',
            FIRSTROW = 2,
                 
      FIELDTERMINATOR = ','

);

I also was having trouble removing quotes (") using the FieldTerminator so I wrote another query to remove the quotes from the fields with the replace function:

Update DTAL_ALL

 set

 DTAL_RRN=replace (DTAL_RRN ,'"',' ')


I don't know if I am being to specific here - all I really need is to create that primary key mentioned above and once created have it reject rows with the same primary key when another bulk insert is run.