Normalization

Consider a relational database schema with a relation $R(A, B, C, D)$. If $\{A, B\}$ and $\{A, C\}$ are the only two candidate keys of the relation $R$, then the number of superkeys of relation $R$ is $\_\_\_\_$ . (answe...

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 $X, Y \subseteq\{P, Q, R, S\}$ Which of th...

In the context of relational database normalization, which of the following statements is/ are true?

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 closure of $F$. To compute the closure of $F$,...

Consider a relational schema team(name, city, owner), with functional dependencies \{name $\rightarrow$ city, name $\rightarrow$ owner}. The relation team is decomposed into two relations, $t 1$ (name, city) and $t 2$ (n...

Consider the following relational schema along with all the functional dependencies that hold on them. $$\begin{aligned} & R 1(A, B, C, D, E):\{D \rightarrow E, E A \rightarrow B, E B \rightarrow C\} \\ & R 2(A, B, C, D)...

Which of the following statements about a relation $R$ in first normal form (1NF) 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 not the empty set. Intersection of $X$ and...

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

Consider a relation R(A, B, C, D, E) with the following three functional dependencies. AB $$\to$$ C ; BC $$\to$$ D ; C $$\to$$ E; The number of superkeys in the relation R is _________.

In a relational data model, which one of the following statements is TRUE?

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 constituent relations according to the follo...

Suppose the following functional dependencies hold on a relation U with attributes P, Q, R, S, and T : P → QR RS → T Which of the following functional dependencies can be inferred from the above functional dependencies?

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

Let the set of functional dependencies F = {QR → S, R → P, S → Q} hold on a relation schema X = (PQRS). X is not in BCNF. Suppose X is decomposed into two schemas Y and Z, where Y = (PR) and Z = (QRS). Consider the two s...

Which of the following is NOT a superkey in a relational schema with attributes $$V, W, X, Y, Z$$ and primary key $$V Y?$$

A database of research articles in a journal uses the following schema. (VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, YEAR, PRICE) The primary key is (VOLUME, NUMBER, STARTPAGE, ENDPAGE) and the following functional depend...

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

Consider an Entity-Relationship (ER) model in which entity sets E 1 and E 2 are connected by an m : n relationship R 12 . E 1 and E 3 are connected by a 1 : n (1 on the side of E 1 and n on the side of E 3 ) relationship...

The maximum number of superkeys for the relation schema $$R(E, F, G, H)$$ with $$E$$ as key is ______.

A prime attribute of a relation scheme $$R$$ is an attribute that appears

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 minimal cover for the set of functional de...

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

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

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

Which of the following is TRUE?

Given the basic $$ER$$ and relational models, which of the following is INCORRECT?

Consider a relation table with a single record for each registered student with a single record for each registered student with the following attributes. $$1.$$ $$Registration$$ $$Num:$$ Unique registration number of ea...

Consider the following relational schemes for a library database. Book ( Title, Author, Catalog_ no, Publisher, Year, Pr ice ) Collection ( Title, Author, Catalog no ) With in the following functional dependencies: $${\r...

Let $$R\left( {A,B,C,D} \right)$$ be a relational schema with the following functional dependencies: $$A \to B,\,\,B \to C,\,\,C \to D$$ and $$D \to B.$$ The decomposition of $$R$$ into $$(A,B), (B,C)$$ and $$(B,D)$$

Let $$R\left( {A,\,B,\,C,\,D,E,P,G} \right)$$ be a relational schema in which the following functional dependencies are known to hold: $$AB \to CD,\,\,DE \to P,\,\,C \to E.\,\,P \to C$$ and $$B \to G.$$ The relational sc...

Which one of the following statements if FALSE?

The following functional dependencies are given : $$\eqalign{ & AB \to CD,\,AF \to D,\,\,DE \to F, \cr & C \to G.\,\,\,\,\,\,\,\,\,\,F \to E.\,\,\,\,\,\,\,\,\,G \to A. \cr} $$ Which one of the following options is false?

Let r be a relation instance with schema R = (A, B, C, D). We define $${r_1} = {\pi _{A,B,C}}\left( r \right)$$ and $${r_1} = {\pi _{A,D}}\left( r \right)$$. Let $$s = {r_1}*{r_2}$$ where * denotes natural join. Given th...

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

Which one of the following statements about normal forms is FALSE?

A table has fields, $$F1, F2, F3, F4, F5,$$ with the following functional dependencies: $$F1 \to F3.\,F2 \to F4.\,\,\,\left( {F1\,.\,F2} \right) \to F5$$ in terms of Normalization, this table is in

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

The relation scheme student Performance (Name, CourseNo, RollNo, Grade) has the following functional dependencies: Name, courseNo $$\,\, \to \,\,$$ grade RollNo, courseNo $$\,\, \to \,\,$$ grade $$\,\,\,\,\,\,\,\,\,\,\,\...

A relation Empdt $$1$$ is defined with attributes empcode (unique), name, street, city, state and pincode. For any pincode, there is only one city and state. Also, for any given street city and the state, there is just o...

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

Relation $$R$$ is decomposed using a set of functional dependencies, $$F,$$ and relation $$S$$ is decomposed using another set of functional dependencies, $$G.$$ One decomposition is definitely $$BCNF,$$ the other is def...

Relation $$R$$ with an associated set of functional dependencies, $$F,$$ is decomposed into $$BCNF.$$ The redundancy (arising out of functional dependencies) in the resulting set of relations is

Consider a schema $$R(A,B,C,D)$$ and functional dependencies $$A \to B\,\,$$ and $$C \to D\,\,$$. Then the decomposition of $$R$$ into $${R_1}\left( {AB} \right)$$ and $${R_2}\left( {CD} \right)$$ is

$$R(A,B,C,D)$$ is a relation. Which of the following does not have a lossless-join, dependency preserving $$BCNF$$ decomposition?

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

Consider the schema $$R = \left( {S\,\,T\,\,U\,\,V} \right)$$ and the dependencies $$S \to T,\,\,T \to U,\,\,U \to V$$ and $$V \to S$$ let $$R =$$ $$(R1$$ and $$R2)$$ be a decomposition such that $$R1 \cap R2 \ne \phi .$...

Let $$R=(A,B,C,D,E,F)$$ be a relation scheme with the following dependencies: $$C \to F,\,E \to A,\,EC \to D,\,A \to B.$$ Which of the following is a key for $$R?$$

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 is the highest normal form satisfied by...

Which normal form is considered adequate for normal relational database design?

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 is the highest normal form satisfied by...

For a database relation $$R(a,b,c,d),$$ where the domains of $$a, b, c, d$$ include only atomic values, only the following functional dependencies and those that can be inferred from them hold: $$a \to c\,\,\,\,\,\,\,\,\...

(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 the Third Normal Form $$(3NF)$$ but not...

An instance of a relational scheme R(A, B, C) has distinct values for attribute A. Can you conclude that A is a candidate key for R?

State True or False with reason. There is always a decomposition into Boyce-codd normal form $$(BCNF)$$ that is lossless and dependency preserving.