I am thrilled to present a session from OUG Harmony 2012 in Finland. I was lucky enough to see this one live, and hope everyone will spend the hour to watch a database legend speak about a big problem in databases. Chris Date describes the three-valued logic approach to missing information (“nulls”) in depth. Both the underlying theory and SQL’s attempt to implement that theory are described. In particular, he shows why the approach is a disastrously bad one and sketches an alternative and logically sounder approach.
Special thanks to Rich Goyette Audio Services for volunteer work in cleaning up the audio as much as possible.