He could also refer to the mere possibility of having duplicates which does not mean there are duplicates. And even then it could be by accident. Of course db design could prevent this. But I guess he is inflating the importance of this issue.
He could also refer to the mere possibility of having duplicates which does not mean there are duplicates. And even then it could be by accident. Of course db design could prevent this. But I guess he is inflating the importance of this issue.