On Fri, Mar 02, 2012 at 10:44:20AM +0100, Christoph P.U. Kukulies scratched on the wall: > When defining a column TEXT PRIMARY KEY (is that possible on TEXT?), > would this imply uniqueness?
Kind of. It implies uniqueness in the SQL sense, which does not include NULLs (remember, NULL != NULL). The SQL term "PRIMARY KEY" should imply both "UNIQUE" and "NOT NULL", but there is a long standing issue in SQLite that allows NULLs in non-integer PRIMARY KEY columns. This allows "duplicate" NULL entries in a PK column. Normally this isn't an issue, as you shouldn't have NULLs in a single-column PK anyways. > Or would I have to write something like TEXT PRIMARY KEY UNIQUE ? No, but to be extra safe you should write "TEXT PRIMARY KEY NOT NULL." -j -- Jay A. Kreibich < J A Y @ K R E I B I.C H > "Intelligence is like underwear: it is important that you have it, but showing it to the wrong people has the tendency to make them feel uncomfortable." -- Angela Johnson _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
