The Design Of SQLite4
"SQLite4 requires all elements of the PRIMARY KEY to be non-null. This is an SQL standard. Due to an oversight in early versions, SQLite3 does not enforce the NOT NULL constraint on PRIMARY KEY columns since by the time the omission was discovered SQLite3 was in such widespread use, activation of NOT NULL enforcement would have broken too many programs."<p>I find this sad, and I wonder what those too many programs are. Why would one put NULL on PRIMARY KEY?