I have a multi-parameter typeclass with a functional dependency: class Multi a b | a -> b I also have a simple, non-injective type synonym family: type family Fam a I want to write an inst...

I've been reading many different sources on how to differentiate relations that are in 3NF/BCNF. And I've so far this is my understanding... I will use this relation as an example... R = {A, B, ...

What are the non-trivial functional dependencies in the following table? A B C 1 1 1 1 1 0 2 3 2 2 3 2 What the basic concept?

I know how to calculate a minimal cover-- ensure each functional dependency only has one attribute on the RHS, remove extraneous/redundant LHS attributes by calculating the closure of each, examini...

I am studying for a test, and this is on the study guide sheet. This is not homework, and will not be graded. Relation Schema R = (A,B,C,D,E) Functional Dependencies = (AB->E, C->AD, D->B, E->C) ...

In the following code: class FD a b | a -> b data Foo a where Foo :: FD a b => b -> Foo a unFoo :: FD a b => Foo a -> b unFoo (Foo x) = x By common sense this should work, since ...

I wonder why the below code does not compile and if there is an implementation mkYVal that GHC would accept. class C x y | x -> y newtype YVal x = YVal { getYVal :: forall y . C x y => y } mk...

In the attached picture there's a symbol I don't understand. To understand additive functional dependency I need to know what the symbol means. Please advice? It's the symbol where it says...

Im just trying to make sure that im thinking of it the right way 1)full dependencies are when one or more primary keys determine another attribute 2)partial dependencies are when one of the prima...

I fabricated a definition that a partial dependency is when fields are indirectly dependent on the primary key or partially dependent but are also dependent on other keys that depend on the primary...

This is a variation on an old chestnut. I wrote it expecting it not to work, but it did. Or is it dodgy? (At GHC 8.6.5.) {-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, FlexibleContexts, F...

A nice true fact about concatenation is that if I know any two variables in the equation: a ++ b = c Then I know the third. I would like to capture this idea in my own concat so I use a functio...

I have a type class that looks a bit like the following: class Foo a b | a -> b where f :: a -> Bool g :: b -> Bool h :: a -> b -> Bool Or at least these are the bits that are ...

Suppose the relation R( K, L, M, N, P), and the functional dependencies that hold on R are: - L -> P - MP -> K - KM -> P - LM -> N Suppose we decompose it into 3 relations as fol...

R = (A, B, C, D, E) The functional dependencies are: A -> B ED -> A BC -> E It then lists the candidate keys as: ACD, BCD, CDE How are these candidate keys derived from the above FDs? S...

I was trying to implement Integers at the type level in Haskell. To start I implemented natural numbers with data Zero data Succ a I then extended this to the integers with data NegSucc a I d...

Given the Relation R with attributes ABCDE. You are given the following dependencies: A -> B, BC -> E, and ED -> A. I already have the answer which is CDE, ACD, and BCD. I just need to know how to ...

Given some type definitions: data A data B (f :: * -> *) data X (k :: *) …and this typeclass: class C k a | k -> a …these (highly contrived for the purposes of a minimal example) functi...

I am trying to find a great resource to study for functional dependency and normalization. Anyone have any idea where should I look to? I am having difficulty differentiating whether a FD is in 1...

Is it possible to create type family instances from a fundep class? For example, let's say that I have the class class A a b | a -> b with some instances (imported an external library) and wa...

Does anyone of them implies the other? My logic is that if all dependencies are preserved, then there is no loss of information and similarly, if decomposition is lossless then no functional depen...

I have played around with TypeFamilies, FunctionalDependencies, and MultiParamTypeClasses. And it seems to me as though TypeFamilies doesn't add any concrete functionality over the other two. (But ...

I'm trying to understand the use of union (the built in predicate) in Prolog. In many cases it seems to fail when it should succeed. It seems it has something to do with the order of the elements o...

I'm taking a database theory course, and it's not clear to me after doing the reading how I can infer keys, given a set of functional dependencies. I have an example problem: Find all keys of the...

At https://web.archive.org/web/20130514174856/http://databases.about.com/cs/specificproducts/g/determinant.htm I found this by Mike Chapple: Definition: A determinant in a database table is any at...