Q. Tuple in relational algebra refers to:

View solution

Q. A relation R on a set X is said to be a partial ordering if R is

View solution

Q. An attribute or set of attributes within one relation that matches the candidate key of some(possibly the same) relation:

View solution

Q. With QBE, inserting records from one or more source tables into a single target table can be achieved by:

View solution

Q. SQL command to delete a column from an existing table:

View solution

Q. Data Scrubbing is

View solution

Q. An attribute A of datatype varchar(20) has the value ‘xyz’, and the attribute B of datatype char(20) has the value “lmnop”, then the attribute A has ............... spaces and attribute B has ............... spaces.

View solution

Q. Data warehouse contains ............... data that is never found in operational environment.

View solution

Q. .................. command is used to remove a relation from SQL database.

View solution

Q. Which of the following statement/s is/are true?

(i) Facebook has the world’s largest Hadoop Cluster.
(ii) Hadoop 2.0 allows live stream processing of Real time data.

Choose the correct answer from the code given below:

View solution

Q. Consider the relation schema R = (A,B,C,D,E,F) on which the following functional dependencies hold:

A → B
B, C → D
E → C
D → A

What are the candidate keys of R?

View solution

Q. Consider the following sequence of two transactions on a bank account (A) with initial balance 20,000 that transfers 5,000 to another account (B) and then apply 10% interest.

(i) T1 start
(ii) T1 A old = 20,000 new 15,000
(iii) T1 B old = 12,000 new = 17,000
(iv) T1 commit
(v) T2 start
(vi) T2 A old = 15,000 new = 16,500
(vii) T2 commit

Suppose the database system crashes just before log record (vii) is written. When the system is restarted, which one statement is true of the recovery process?

View solution

Q. A clustering index is defined on the fields which are of type:

View solution

Q. In RDBMS, which type of Join returns all rows that satisfy the join condition?

View solution

Q. In a Hierachical database, a hashing function is used to locate the .................

View solution

Q. Relations produced from E - R Model will always be in ..............

View solution

Q. Consider the following schedules involving two transactions.

S1 : r1(X) ; r1(Y) ; r2(X) ; r2(Y) ; w2(Y) ; w1(X)
S2 : r1(X) ; r2(X) ; r2(Y) ; w2(Y) ; r1(Y) ; w1(X)

Which one of the following statements is correct with respect to above?

View solution

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

a → c
b → d

The relation is in ...............

View solution

Q. A many-to-one relationship exists between entity sets r1 and r2. How will it be represented using functional depedencies if Pk(r) denotes the primary key attribute of relation r?

View solution

Q. Database systems that store each relation in a separate operating system file may use the operating system’s authorization scheme, instead of defining a special scheme themselves. In this case, which of the following is false?

View solution