On Fri, Mar 10, 2006 at 04:37:36PM -0800, Darren Duncan wrote: > 3. There is no such thing as a NULL. > > 3.1 All logic is 2VL (true, false) not 3VL (true, false, unknown).
There is no such thing as null, really? So, when you do an outer join between two tables, which in SQL would produce null columns in the result set, what do YOU propose producing instead of those nulls? Perhaps I missed it, but in my brief reading of some of Date's work, I never saw him answer that question. > 3.4 Missing data can be either represented with the data type's > empty value, or a table column that may possibly be unknown can be > split into a separate related table, that only has records when the > value is known. > > 3.5 All variables default to a reasonable valid value for their type > if not explicitly set, such as the number zero or the empty string. -- Andrew Piskorski <[EMAIL PROTECTED]> http://www.piskorski.com/
