What is the deal with NULLs?
A recent thread on pgsql-hackers warrants some more extensive discussion. In the past, I’ve criticized NULL semantics, but in this post I’d just like to explain some corner cases that I think you’ll...
View ArticleTemporal Keys, Part 1
“Schedule conflict” — it’s one of the simplest and most common constraints for business or any other organization. One person cannot be in two places at the same time; and in many cases a only a single...
View ArticleScalability and the Relational Model
The relational model is just a way to represent reality. It happens to have some very useful properties, such as closure over many useful operations — but it’s a purely logical model of reality. You...
View ArticleTemporal PostgreSQL Roadmap
Why are temporal extensions in PostgreSQL important? Quite simply, managing time data is one of the most common requirements, and current general-purpose database systems don’t provide us with the...
View ArticleWhy PostgreSQL Already Has Query Hints
This is a counterpoint to Josh’s recent post: Why PostgreSQL Doesn’t Have Query Hints. I don’t really disagree, except that I think that there are many different definitions of “hints” floating around,...
View ArticleDatabase for a Zoo: the problem and the solution
Let’s say you’re operating a zoo, and you have this simple constraint: You can put many animals of the same type into a single cage; or distribute them among many cages; but you cannot mix animals of...
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