functional dependency

Let $P, Q, R$ and $S$ be the attributes of a relation in a relational schema. Let $X \rightarrow Y$ indicate functional dependency in the context of a relational database, where $X...

In the context of schema normalization in relational DBMS, consider a set $F$ of functional dependencies. The set of all functional dependencies implied by $F$ is called the closur...

The symbol → indicates functional dependency in the context of a relational database. Which of the following options is/are TRUE?

A functional dependency F: X → Y is termed as a useful functional dependency if and only if it satisfies all the following three conditions: * X is not the empty set. * Y is not th...

The symbol → indicates functional dependency in the context of a relational database. Which of the following options is/are TRUE?

A functional dependency $F: X \to Y$ is termed as a useful functional dependency if and only if it satisfies all the following three conditions: $X$ is not the empty set. $Y$ is no...

Consider the relation R(P, Q, S, T, X, Y, Z, W) with the following functional dependencies. PQ → X; P → YX; Q → Y; Y → ZW Consider the decomposition of the relation R into the cons...

Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE?

Consider the relation $$X\left( {P,Q,R,S,T,U} \right)$$ with the following set of functional dependencies $$\eqalign{ & F = \left\{ \, \right. \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\...

Given the following two statements: $$S1:$$ Every table with two single-valued attributes is in $$1NF, 2NF, 3NF$$ and $$BCNF.$$ $$S2:$$ $$AB \to C,\,\,D \to E,\,\,E \to C$$ is a mi...

Consider the relation schema $$R = \left( {E,\,F,\,G,\,H,\,I,\,J,\,K,L,\,M,\,N} \right)$$ and the set of functional dependencies $$\left\{ {\left\{ {E,F} \right\} \to \left\{ G \ri...

Relation $$R$$ has eight attribution $$ABCDEFGH.$$ Fields of $$R$$ contain only atomic values. $$F = \left\{ {CH \to G,\,\,A \to BC,\,B \to CFH,\,\,E \to A,\,\,F \to EG} \right\}$$...

The following functional dependencies hold for relations R(A, B, C) and S(B, D, E): $$$\eqalign{ & B \to A \cr & A \to C \cr} $$$ The relation R contains 200 tuples and the relatio...

The following functional dependencies are given : $$\eqalign{ & AB \to CD,\,AF \to D,\,\,DE \to F, \cr & C \to G.\,\,\,\,\,\,\,\,\,\,F \to E.\,\,\,\,\,\,\,\,\,G \to A. \cr} $$ Whic...

Consider a relation scheme $$R = \left( {A,\,B,\,C,\,D,\,E,\,H} \right)$$ on which the following functional dependencies hold: $$\left\{ {A \to B,\,\,BC \to D,\,\,E \to C,\,\,D \to...

In a schema with attributes $$A, B, C, D,$$ and $$E,$$ following set of functional dependencies are given $$\eqalign{ & \,\,\,A \to B \cr & \,\,\,A \to C \cr & CD \to E \cr & \,\,\...

Consider the following functional dependencies in a database. $$\eqalign{ & \,\,\,\,Date\,\,of\,\,Birth\,\, \to \,\,Age \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Ag...

Given the following relation instance $$\eqalign{ & X\,\,\,\,\,Y\,\,\,\,\,Z \cr & \,\,1\,\,\,\,\,\,4\,\,\,\,\,\,2 \cr & \,\,1\,\,\,\,\,\,5\,\,\,\,\,\,3 \cr & \,\,1\,\,\,\,\,\,6\,\,...

Consider the following database relations containing the attributes Book–id Subject–Category–of–book Name–of–Author Nationality–of–Author With book–id as the primary key. (a) What...

Consider the following database relations containing the attributes Book–id Subject–Category–of–book Name–of–Author Nationality–of–Author With book–id as the primary key. (a) What...

(a) Consider the relation scheme $$R(A, B, C)$$ with the following functional dependencies: $$\eqalign{ & A,B \to C \cr & \,\,\,\,\,\,C \to A \cr} $$ Show that the scheme $$R$$ is...