It may violate the documentation. I don't have a chapter and verse that documents otherwise. But I suspect that given the value the SQLite team places on backward compatibility, it is unlikely that this "bug" or "feature" (depending on your point of view) is going to change, as it would break untold numbers of applications that rely on the functionality. The same reason the fact that INTEGER PRIMARY KEY NULL handling has never been changed, or by default FOREIGN KEY is off...