A general API for relational joins

haskellforall.com

28 pointslelf4 comments

Cool read - but you should be careful modeling Tables as things with an "id". The relational algebra is about sets of tuples. The fact that there is an index that one can use to make joins go faster is an (important) implementation detail but divorced from the data model.

The fact that these are sets is an important distinction and enables things like predicate pushdown and other important optimizations. Would be interesting to see a Selinger-style cost-based optimizer built in Haskell!

The only reason I chose `Table` was just not to reuse the word `Map`. I agree that there should be a separate abstraction for unindexed sets of tuples. I probably should have called it `IndexedTable` or something.

Offtopic (because I cannot get to the topic) - why does Barracuda classify www.haskellforall.com as "Illegal Drugs"?

Learning Haskell can alter your brain permanently. Just say no!

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