``` .version create table a( id text primary key null ) without rowid; insert into a values('whatever'); insert into a values(null); create table b( id text primary key null ); insert into b values('whatever'); insert into b values(null); ``` Both tables the same except for `WITHOUT ROWID` for table `a`. I get following error for table `a` only. ``` SQLite 3.34.0 2020-12-01 20:57:24 1c7e6243ec89b4fa3599eaebbe1021bdca5b0359825e1ce582db1b1f92067fac msvc-1800 Error: near line 6: NOT NULL constraint failed: a.id ``` Why do they behave differently when both are primary keys that accept nulls?