Recent questions tagged goclasses-databases-practice-questions

Consider $R(A,B,C,D,E)$ with $\Sigma=\{A\to B,\ AE\to D,\ B\to E,\ AD\to E,\ CD\to A,\ AB\to D,\ E\to B\}$.Which of the following correctly gives a lossless, dependency-p...

Which statement correctly describes the guarantee of the standard BCNF decomposition procedure?Every relation has a decomposition that is simultaneously BCNF, lossless an...

Consider $R(A,B,C,D,E,F)$ with $F=\{A\to B,\ A\to C,\ BC\to E,\ BC\to D,\ E\to F,\ BC\to F\}$.Suppose the following BCNF decomposition is used:$R_1(B,C,E)$$R_2(B,C,F)$$R_...

Consider $R(A,B,C,D,E,F,G)$ with $F=\{AB\to CF,\ CD\to EA,\ E\to ABC,\ B\to F,\ C\to D\}$.Suppose $R$ is decomposed into $R_1(A,B,C,D,E,G)$ and $R_2(B,F)$.Which statement...

Consider $R(A,B,C,D,E,F,G)$ with $F=\{BCD\to A,\ BC\to E,\ A\to F,\ F\to G,\ C\to D,\ A\to G\}$.Which of the following statements are correct after applying the $\text{3N...

Consider $\text{GSL}(D,M,N_1,N_2,G_1,G_2,C_1,C_2,E,R)$, where $M$ is the primary key, together with$M\to D,$$E\to R,$$N_1\to G_1C_1,$$N_2\to G_2C_2,$$G_1C_1\to N_1,$$G_2C...

Consider $R(A,B,C,D,E)$ with $F=\{AB\to C,\ BC\to D,\ CD\to E,\ DE\to A\}$.Suppose the BCNF decomposition begins with the violating FD $:CD\to E$.Which set of relations i...

Consider $R(A,B,C,D,E)$ with $F=\{D\to B,\ DE\to A,\ C\to AD\}$.Which of the following is a valid BCNF decomposition of $R$?$\{DB,\ ADE,\ CE\}$ $\{CDA,\ DEB\}$ $\{DB,\ AC...

Consider $R(I,N,W,S,Q,T,P,R)$ with $F=\{N\to W,\ IN\to S\}$.Which of the following is the BCNF decomposition produced by successively removing these violations?$R_1(N,W)$...

Consider $R(A,B,C,D)$ with $F=\{A\to B,\ C\to D\}$. Which of the following is a correct BCNF decomposition of $R$?$R_1(A,B)$$R_2(C,D)$$R_3(A,C)$ $R_1(A,B,C)$$R_2(C,D)$ $R...

Consider $R(A,B,C,D,E,F,G,H,I,J)$ with $F=\{AB\to CD,\ D\to EFG,\ FG\to H,\ A\to I,\ AB\to EG,\ AI\to IJ\}$. The candidate key is $AB$.Which of the following is a valid $...

Consider $R(A,B,C,D,E,F,G,H,I,J)$ with $F=\{AB\to C,\ A\to DE,\ B\to F,\ F\to GH,\ D\to IJ\}$. The candidate key is $AB$.Which of the following is a valid $\text{2NF}$ de...

After representing the attributes atomically, consider $\text{Inventory(PartNbr, Warehouse, Location, QOH, Weight, PartColor)}$ with $\text{PartNbr} \to \text{Weight, Par...

Consider $R(A,B,C,D,E)$ with $F=\{A\to E,\ EC\to BD,\ D\to C\}$. The candidate keys are $AC$ and $AD$. Which decomposition correctly removes the $\text{2NF}$ violation?$R...

Consider $\text{CLASS(CourseNo, SectionNo, RoomNo, Capacity)}$ with candidate key $\text{(CourseNo, SectionNo)}$ and functional dependency $\text{RoomNo} \to \text{Capaci...

Consider $R(A,B,C,D,E,F,G,H)$ with $F=\{AB\to CD,\ AC\to DE,\ EF\to AG\}$.The decomposition is $R_1(A,C,D,E),$ $R_2(A,B,C),$ $R_3(A,B,F,G,H)$.Which statement correctly de...

Consider $R(A,B,C,D,E,F,G)$ with $F=\{AC\to BD,\ BC\to E,\ BE\to DF,\ AG\to EB\}$ and decomposition $R_1(A,B,C,D),$ $R_2(A,B,C,E,G),$ $R_3(B,E,F),$ $R_4(A,E,G)$.Which of ...

Consider $R(A,B,C,D,E,F)$ with $F=\{A\to C,\ CE\to D,\ CD\to A,\ DF\to A\}$.The decomposition is $R_1(A,B,C,D),$ $R_2(A,D,E),$ $R_3(B,C,E,F)$.Which statement is correct?T...

Consider the relation $R(T,I,G,E,R,S)$ with $F=\{G\to ES,\ RT\to I,\ IR\to E\}$.It is decomposed into $R_1(T,E),$ $R_2(I,G),$ $R_3(I,E,R,S)$.What does the Chase Test conc...

Consider $R(S,N,C,P,X,Y,Q)$ with $F=\{S\to NC,\ P\to XY,\ SP\to Q\}$.The relation is decomposed into $R_1(S,N,C),$ $R_2(P,X,Y), $ $R_3(S,P,Q)$.Which statement is correct?...

Consider $R(A,B,C,D,E)$ with $F=\{A\to DE,\ BE\to C,\ D\to B,\ C\to A\}$.The relation is decomposed into $R_1(A,B,C)$ and $R_2(A,D,E)$.Which of the following statements a...

Consider $R(A,B,C,D,E,F)$ with $F=\{C\to D,\ A\to B,\ B\to EF,\ F\to A\}$.Suppose $R$ is decomposed into $R_1(A,B,D,E)$ and $R_2(A,B,C,F)$. The decomposition is currently...

Consider the binary decomposition$R(A,B,C,D)\to R_1(A,C,D),R_2(B,C)$.Which of the following statements are correct?If $C$ is a candidate key for $R_1$, the decomposition ...

Consider $R(A,B,C,D)$ with $F=\{B\to C,\ D\to A\}$.The relation is decomposed into $R_1(B,C)$ and $R_2(A,D)$.Which of the following statements are correct?The decompositi...

Consider $X(A,B,C,D,E,F)$ with $F=\{AB\to CD,\ CD\to EF\}$.The relation is decomposed into $X_1(A,B,C,D)$ and $X_2(C,D,E,F)$.Which statement is correct?The decomposition ...

Consider relation $R(A,B,C,D,E,F)$ with$A\to B$$A\to C$$F\to D$$F\to E$Suppose $R$ is decomposed into $R_1(A,B,C)$ and $R_2(D,E,F)$.Which statement best describes this de...

A redundant relation is decomposed appropriately to improve its logical database design.Which of the following benefits can be relied upon as a purpose of the decompositi...

Consider the single relation containing $\text{Course, Teacher, Room, Hour, StudentID, Grade}$.\[\begin{array}{|c|c|c|c|c|c|}\hline\text{Course} & \text{Teacher} & \text{...

A relation contains four tuples for course $\text{CS 186}$, and every tuple stores the teacher as $\text{Hellerstein}$.Lets consider the set of data is as follows :\[\beg...

Consider $\text{Postings(post, position, user, ptext)}$.Two aliases of this relation are used:$\text{P1 = Postings}$$\text{P2 = Postings}$Consider the query:SELECT count(...