Jeffrey Tenny <[EMAIL PROTECTED]> writes: > What are the performance tradeoffs (storage space, query speed) of using > a NULL enabled column versus a NOT-NULL column with a sentinel integer > value? > Not that it matters, but in the event where the column values matter, > the numberic value is a foreign key. Advice on that welcome too.
In that case you want to use NULL, because the foreign key mechanism will understand that there's no reference implied. With a sentinel value you'd have to have a dummy row in the master table --- which will cause you enough semantic headaches that you don't want to go there. The performance difference could go either way depending on a lot of other details, but it will be insignificant in any case. Don't screw up your database semantics for it. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend