Violation of PRIMARY KEY constraint????

Question

I am using bulkcopy to import data into SQL server database.The data i'm trying to import contains student numbers and the modules that they are registerd for.A student can be registered for many modules(which means one student number can appear many times on the table).Problem is when i try to import my spradsheet my application throws a "Violation of PRIMARY KEY constraint" error.
How do i fix this

Answer 1

My PC har to communicate with a kit. For instance, i have to write a random value of power consumption in the textbox, and send that value to the kit.

It is important for the kit to receive the values as a number, because the kit controls a "plastic made" flower, which will react dependent on the power value. So the only job i will do with C#, is to write the values in the textbox and send those values with pressing "send" button.

Answer 2

Please elaborate it more