sqlbulkcopy insert into sql server

在我的sqlserver表中我定义了以下列:stationid、dateofevent itemname sitename,点击

To populate above table , we have a c# application. In which inserts data in a loop. Data comes from remote machine and once data received by server(another c# application) , it imserts into sql server and send back OK response to remote client. When client receives response , it archives data into another table and deletes the data from actual table.
Incase if client fails to archive , stored procedure from server side will take care of preventing duplicate record insert.
    Set @previousClickCount=( SELECT Clicks FROM [Analytics] as pc
                                 where DATEADD(dd, 0, DATEDIFF(dd, 0, [DateOfEvent]))=@date
                                 and ItemType=@type
                                 and stationId = @stationId 
                                 and ItemName=@itemName 
                                 and SiteName=@siteName)
    If @previousClickCount Is Null
        Begin
        -- Row for this item is not found in DB so inserting a new row
            Insert into Analytics(StationId,DateOfEvent,WeekOfYear,MonthOfYear,Year,ItemType,ItemName,Clicks,SiteName)
            VALUES(@stationId,@date,DATEPART(wk,@date),DATEPART(mm,@date),DATEPART(YYYY,@date),@type,@itemName,@clicks,@siteName)
        End
Later we decided to move to bulk insert in server side code. So that we can avoid looping.             
bulkCopy.DestinationTableName = SqlTableName;
bulkCopy.BatchSize = 1000;
bulkCopy.BulkCopyTimeout = 1000;
bulkCopy.WriteToServer(dataTable);
But incase client side failed to archive data then server will insert duplicate record.Is there any way to check this in bulk insert or whether can we add any constraint like,insert only if the itemname not present for the particular date then insert.

的问候Sangeetha