# Recent questions tagged database-normalization

1
Suppose the following functional dependencies hold on a relation $U$ with attributes $P,Q,R,S$, and $T$: $P \rightarrow QR$ $RS \rightarrow T$ Which of the following functional dependencies can be inferred from the above functional dependencies? $PS \rightarrow T$ $R \rightarrow T$ $P \rightarrow R$ $PS \rightarrow Q$
1 vote
2
Consider the relation $R(P,Q,S,T,X,Y,Z,W)$ with the following functional dependencies. $PQ\rightarrow X;\quad P\rightarrow YX;\quad Q\rightarrow Y; \quad Y\rightarrow ZW$ Consider the decomposition of the relation $R$ into the constituent relations according to ... , but $D_2$ is a lossless decomposition Both $D_1$ and $D_2$ are lossless decompositions Both $D_1$ and $D_2$ are lossy decompositions
1 vote
3
For a database relation $R(a,b,c,d)$ where the domains of $a,b,c$ and $d$ include only atomic values, only the following functional dependencies and those that can be inferred from them hold. $a \rightarrow c$ $b \rightarrow d$ The relation is in First normal form but not in second normal form Second normal form but not in third normal form Third normal form None of the above
1 vote
4
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 $R$? $CD$ $EC$ $AE$ $AC$
5
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: $a\to c\\b\to d$ the relation is in first normal form but not in second normal form. second normal form but not in third normal form. third normal form. none of these.
6
Normalization from which is based on transitive dependency is classified as: First normal form. Second normal form. Fourth normal form. Third normal form.
7
In functional dependency between two sets of attribute $A$ and $B$ then set of attributes $A$ of database is classified as: top right side down left side left hand side right hand side
8
Which one of the following statements about normal forms is FALSE? BCNF is stricter than $3$NF. Lossless, dependency-preserving decomposition into BCNF is always possible. Lossless, dependency-preserving decomposition into $3$NF is always possible. Any relation with two attributes is BCNF.
9
If attribute of relation schema $R$ is member of some candidate key then this type of attributes are classified as: atomic attribute candidate attribute non-prime attribute prime attribute
10
Process of analyzing relation schemas to achieve minimal redundancy and insertion or update anomalies is classified as: normalization of data. denomination of data. isolation of data. de-normalization of data.
1 vote
11
Rule which states that addition of same attributes to right side and left side will result in other valid dependency is classified as referential rule inferential rule augmentation rule reflexive rule
12
If every functional dependency in set $E$ is also in closure of $F$ then this is classified as $FD$ is covered by $E$ $E$ is covered by $F$ $F$ is covered by $E$ $F$ plus is covered by $E$
13
Considering relational database, functional dependency between two attributes $A$ and $B$ is denoted by $A\to B$ $B\gets A$ $AB\to R$ $R\gets AB$
14
Which one of the following statements are not correct? $S1$: $3$NF decomposition is always lossless join and dependency preserving. $S2$: $3$NF decomposition is always lossless join but may or may not be dependency preserving. $S3$: BCNF decomposition is always lossless join and dependency ... but may or may not be dependency preserving. Only $S1$ Only $S4$ Both $S1$ and $S4$ Both $S2$ and $S3$
1 vote
15
Which of the following is TRUE? Every relation in $3$NF is also in BCNF A relation R is in $3$NF if every non-prime attribute of R is fully functionally dependent on every key of R Every relation in BCNF is also in $3$NF No relation can be in both BCNF and $3$NF.
16
Consider the relational schema $R(A B C D)$ with following $FD$ set $F=\{A \to CE, B \to D, AE \to D\}$. Identify the highest normal form satisfied by the relation $R$. $2$NF BCNF $3$NF $1$NF
17
Consider the relational schema $\text{R(A B C D)}$ with following functional dependency set $F=\{A\rightarrow BC,C\rightarrow D\};$ The relation $\text{R}$ is in $2$NF BCNF $3$NF $1$NF
18
Which one is correct w.r.t. RDBMS? primary key $\subseteq$ super key $\subseteq$ candidate key primary key $\subseteq$ candidate key $\subseteq$ super key super key $\subseteq$ candidate key $\subseteq$ primary key super key $\subseteq$ primary key $\subseteq$ candidate key
19
For database relation $R(A,B,C,D)$ where the domains of $A,B,C$ and $D$ include only atomic values, only the following functional dependencies and those that can be inferred from them are: $A \rightarrow C$ $B \rightarrow D$ The relation $R$ is in First ... well as in second normal form Second normal form but not in third normal form. Both in second normal form as well as in third normal form.
20
Consider a relational table $R$ that is in $3NF$, but not in BCNF. Which one of the following statements is TRUE? $R$ has a nontrivial functional dependency $X \rightarrow A$, where $X$ is not a superkey and $A$ is a prime attribute. $R$ has a nontrivial functional dependency ... $X$ is a proper subset of some key A cell in $R$ holds a set instead of an atomic value.
21
If every non-key attribute functionally dependent on the primary key, then the relation will be in First normal form Second normal form Third normal form Fourth Normal form
1 vote
22
The process of normalization is used to Enhance the number of relations Determine the relationship between different relations Minimize the redundancies & eliminate anomalies Ease the computational work.
23
The multivalued dependencies (MVDs) can be eliminated using ______ normal form on _____ normal form relations. $1$st, $2$nd $2$nd, $3$rd $3$rd, BCNF $4$th, BCNF
Consider the relation $R\left ( A,B,C,D,E \right )$ with functional dependencies $F=${ $A\rightarrow B$ $BC\rightarrow E$ $ED\rightarrow A$ } Number of additional relation required to convert it into lossless , dependency preserving $3NF$ decomposition is _____________ What is meaning of additional relation (Here no table mentioned previously)??