These are Data Base Management System Week 1 Assignment Answers
Q1. A relation R has 2 candidate keys with 1 attribute each. There are 6 possible super keys of R. What is the total number of attributes in R? a) 2 b) 3 c) 4 d) 5
Answer: b) 3
Q2. Consider the following instances of the relation: SEMESTER1 (Student, Marks) and SEMESTER2(Student, Marks) Which of the following Relational Algebra produces the Name and SEMESTER1 Marks of only those Students who did not appear in SEMESTER2? a) (II_Student (SEMESTER2) — II_Student (SEMESTER1)) >< SEMESTER1 b) (II_Student (SEMESTER2) — II_Student (SEMESTER1)) >< SEMESTER2 c) (II_Student (SEMESTER1) — II_Student (SEMESTER2)) >< SEMESTER2 d) (II_Student (SEMESTER1) — II_Student (SEMESTER2)) >< SEMESTER1
These are Data Base Management System Week 1 Assignment Answers
Q3. Consider the following instance of the relation Counters(CNo, Item, Price, Category) Identify the valid primary key for the relation Counters(CNo, Item, Price, Category) from the given instance. a) {CNo, Item} b) {Item, Price} c) {Price, Category} d) {CNo, Item, Category}
Answer: b) {Item, Price}
Q4. Consider the following instance of the relation Seating(SNo, Preference, Coach, Name) Identifying the primary key from the given instance, select the tuple that can NOT be inserted to Seating. a) (11, WS, D1, Harsh S.) b) (2, NP, D2, Anukul K.) c) (6, NWS, D2, Raima H.) d) (6, NULL, NULL, NULL)
These are Data Base Management System Week 1 Assignment Answers
Q5. Consider the following RA: II_track(ocategory=_’Pop’ (Music)) Which of the following statements is true? a) Displays the details of all Music from Pop Category b) Displays the details of at least one Music from Pop Category c) Displays at most one track from Pop Category d) Displays all the tracks from Pop Category
Answer: d) Displays all the tracks from Pop Category
Q6. Let R1 (X,Y) and R2(A,B,C) be two relations in a schema. The primary keys are shown underlined. Let C be a foreign key in R2 referring to R2. Suppose, there is no violation of the above referential integrity constraint in the corresponding relation instances r1 and r2. Which one of the following relational algebra expressions would necessarily produce an empty relation? a) II_X(r1) —II_C(r2) b) II_C(r2) —II_X(r1) c) II_X(r1><r2) d) II_C(r1><r2)
These are Data Base Management System Week 1 Assignment Answers
Q7. Consider the following relations: Parts(PartID, Name, Price ). Supplier(SupID, Name, Location). Order(SupID, PartID, Quantity) . If SupID and PartID together are used to uniquely identify a row in Order table, which of the following option is correct for describing such key in Order table? a) Alternate key b) Composite key c) Compound key d) Surrogate key
Answer: c) Compound key
Q8. Consider the following table: Identify the correct operation(s) which produces the following output from the above relation. a) II_(Address=”Kolkata’) ^ _(Age>25)(StudentDetails) b) II_(Address=”Kolkata’) v _(Age>25)(StudentDetails) c) o-_(Address=”Kolkata’) ^ _(Age>25)(StudentDetails) d) o-_(Address=”Kolkata’) v _(Age>25)(StudentDetails)
Answer: d) o-_(Address=”Kolkata’) v _(Age>25)(StudentDetails)
Q9) Consider the following tables: Identify the correct operation(s) which will be produce the following output from the above two relations. a) (Student x Department) b) II_(StudName, Student.DeptName, Fees) (o-_Student.DeptName = Department.DeptName) (Student x Department) c) o-_(StudName, Student.DeptName, Fees)(Student >< Department) d) (Student >< Department)
Answer: b), d) b) II_(StudName, Student.DeptName, Fees) (o-_Student.DeptName = Department.DeptName) (Student x Department) d) (Student >< Department)
These are Data Base Management System Week 1 Assignment Answers
Q10. Which of the following can be a candidate key for the following instance? a) {StudName} b) {DeptName} c) {StudName, DeptName} d) {Address, Age}
These are Data Base Management System Week 1 Assignment Answers
Q1) Which level of abstraction describes types of data that are stored in the Database? a) Physical level b) Logical level c) View level d) Abstraction level
Answer: a) Physical level
Q2) Identify the valid primary key for the relation paper_info from the given instance. a) paper_id b) paper_id, corresponding Author c) conference_id, corresponding_Author d) paper_id, conference_id
Answer: a) paper_id
These are Data Base Management System Week 1 Assignment Answers
Q3) Identify the correct statement/s. a) Project (pCode, pName) is an instance of a relation schema. b) Project (pCode, pName) is an example of a physical schema. c) (2245, HardFort) is an instance of a relation schema. d) (2245, HardFort) is an example of a logical schema.
Answer: a) Project (pCode, pName) is an instance of a relation schema.
Q4) Consider a relation Vehicle (VID, Model, Speed, Color) where the superkeys are as follows: {VID}, {VID, Model}, {Speed, Color}, {Speed, Color, Model}. Select the possible candidate key(s). a) {VID} b) {Speed} c) {Color} d) {Speed, Color}
Answer: a) {VID}
These are Data Base Management System Week 1 Assignment Answers
Q5) Consider the following relations: Book (ISBN, Title, Pages) BookGenre (ISBN, Genre) What does the following relational algebra expression represent? IIISBN((Pages>100 Book) (Genre-Fiction/BookGenre)) a) Find the ISBN of all Book with more than 100 Pages. b) Find the ISBN of all Book with more than 100 Pages or are of Genre ‘Fiction’. c) Find the ISBN of all Book with more than 100 Pages but are not of Genre ‘Fiction’. d) Find the ISBN of all Book with more than 100 Pages and are of Genre ‘Fiction’.
Answer: d) Find the ISBN of all Book with more than 100 Pages and are of Genre ‘Fiction’.
Q6) Consider the following relational schema: ImageCode (ImageID, Name) ImageBook (BookID, Image ID, Page) What will be the Relational Algebra equivalent to the following statement? “Find the names of all Images on Page 100.” a) Name (ImageCode Page=100 (ImageBook)) X b) Name (Ipage=100 (ImageCode) ImageBook) c) IIName(IIpage=100 (ImageCode) ▷ ImageBook) d) IIName (Image Code Page=100 (ImageBook))
These are Data Base Management System Week 1 Assignment Answers
Q7) Consider the following tables: Which of the following operations will return S1 itself? a) S2-(S2-S1) b) S1-(S2-S1) c) S1-(S1-S2) d) S2-(S1-S2)
Answer: c) S1-(S1-S2)
Q8) Consider the following tables: Identify the correct operation(s) which will be produce the following output from the above relations. a) (#Faculties>=20000) (UniversitiesDetails) b) (#Faculties>20000) (Universities Details) c) IIStateName, #State Universities, #Faculties (#Faculties>=20000) (Universities Details) d) IlStateName, #State Universities, #Faculties (#Faculties> 20000) (UniversitiesDetails)
Answer: c) IIStateName, #State Universities, #Faculties (#Faculties>=20000) (Universities Details)
Q9) Consider the following tables: Identify the correct operation(s) which will be produce the following output from the above two relations. a) Details Details2 b) Details – Details₁ c) (Details₁ U Details ₂) n (Details₁ Details₂) d) (Details1 Details2) U (Details2 – Details 1)
Answer: d) (Details1 Details2) U (Details2 – Details 1)
These are Data Base Management System Week 1 Assignment Answers
Q10) Which of the following can be a candidate key for the following instance? a) {StateName} b) {#State Universities} c) {#Faculties} d) {StateName, #Central Universities, #State Universities}
Answer: a) {StateName}
These are Data Base Management System Week 1 Assignment Answers
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