Consider the following schema :Sailors(sid, sname, rating, age)Boats(bid, bname, colour)Reserves(sid, bid, day)Two boats can have the same name but the colour differentiates them.The two relationsρ(Tempsids, (πsid, bid Reserves) / (πbid (σname = ‘Ganga' Boats))),πsname (Tempsids ⋈ Sailors)If / is division operation, the above set of relations represents the query

Names of sailors who have not reserved any Ganga boat

Names of sailors who have reserved all boats called Ganga

Names of sailors who have reserved at least one Ganga boat

Names of sailors who have reserved at most one Ganga boat

Consider the following schema :Sailors(sid, sname, rating, age)Boats(b

1.	Consider the following schema :Sailors(sid, sname, rating, age)Boats(bid, bname, colour)Reserves(sid, bid, day)Two boats can have the same name but the colour differentiates them.The two relationsρ(Tempsids, (πsid, bid Reserves) / (πbid (σname = ‘Ganga' Boats))),πsname (Tempsids ⋈ Sailors)If / is division operation, the above set of relations represents the query
A.	Names of sailors who have reserved all boats called Ganga
B.	Names of sailors who have not reserved any Ganga boat
C.	Names of sailors who have reserved at least one Ganga boat
D.	Names of sailors who have reserved at most one Ganga boat
Answer» B. Names of sailors who have not reserved any Ganga boat

Discussion

No Comment Found

Related MCQs

Given the following two statements about SQL(a) An SQL query can contain HAVING clause only if it has GROUP BY clause.(b) In an SQL query “SELECT_FROM_WHERE_GROUP BY_HAVING”, HAVING is executed before WHERE.Which of the following is correct?
Consider the following statements S1 and S2 about the relational data model:S1: A relation scheme can have at most one foreign key.S2: A foreign key in a relation scheme R cannot be used to refer to tuples of R.Which one of the following choices is correct?
_______ SQL command changes one or more fields in a record.
Consider the following SQL query:SELECT title, nameFROM EmployeeORDER BY title, name DESC:In output of above query the different titles are listed in ___________ order the names of employees having same title are listed in ___________ order.
_______ symbol is used to see every column of a table.
Consider a relational table with a single record for each enrolled student with the following attributes1. Eno: Unique enrollment number for each enrolled student2. UID: Unique identity number at the national level for each citizen3. Acc_no: Unique account number at the bank. A student can have multiple accounts or joint accounts.. This attributes stores the primary account number.4. Name: Name of the student5. Phone: Phone number of the studentWhich of the following options is incorrect?
Consider a relational database containing the following schemes.CataloguesnopnoCostS1P1150S1P250S1P3100S2P4200S2P5250S3P1250S3P2150S3P5300S3P4250 SupplierssnosnamelocationS1M/s Royal furnitureDelhiS2M/s Balaji furnitureBangaloreS3M/s Premium furnitureChennai PartspnoPnamePart_specP1TableWoodP2ChairWoodP3TableSteelP4AlmirahSteelP5AlmirahWood The primary key of each table is indicated by underling the constituent fields.SELECT s.sno, s.snameFROM Suppliers s, Cataloque cWHERE s.sno = c.sno AND Cost > (SELECT AVG (cost)FROM CataloqueWHERE pno = ‘P4’GROUP BY pno);The number of rows returned by the above SQL query is
Given two relations R1(A, B) and R2(C, D), the result of following querySelect distinct A, Bfrom R1, R2is guaranteed to be same as R1 provided one of the following condition is satisfied.
Consider the following schema :Sailors(sid, sname, rating, age)Boats(bid, bname, colour)Reserves(sid, bid, day)Two boats can have the same name but the colour differentiates them.The two relationsρ(Tempsids, (πsid, bid Reserves) / (πbid (σname = ‘Ganga' Boats))),πsname (Tempsids ⋈ Sailors)If / is division operation, the above set of relations represents the query
A minimal super key (i.e., one of the super keys for which no proper subset is a super key) is called:

Discussion

No Comment Found

Related MCQs

Reply to Comment