In SSIS I have a lookup transform which performs the function of only inserting new data into the table, call it tableY. So the process is the following:
0) Aggregate (group by) the primary key for the input row
1) Do a lookup with the current input row on tableY using the primary key
2) Insert the input row if there is not a match (the current row does not exist in tableY)
I get the error that I have "violated the integrity constraints of the primary key column"
How is this possible since all inputs are unique and the output of the transform is "lookup no match output"?