Database Management Systems
Questions 341 to 350
A foreign key must
(a) Be numeric
(b) Be unique
(c) Be defined in all tables within the
database
(d) Match the field value of a primary key in
a related table
(e) Contain only one attribute.
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Within a table, the primary key
must be unique so that it will identify each row. Which of the following
constraints exhibits the above criterion?
(a)
Referential integrity (b)
Entity integrity
(c)
Enforced integrity (d)
Domain integrity
(e)
Check integrity.
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You want the contents of the PRODUCT table listed by
P_Price in ascending order listing P_CODE, P_DESCRIPT, P_INDATE, and P_PRICE
and with P_INDATE < ‘8-oct-05’.
The
command will be
(a) Select p_code, p_descript, p_indate,
p_price from product where P_INDATE < ‘8-oct-05’ sequence by p_price;
(b) Select p_code, p_descript, p_indate,
p_price from product where P_INDATE < ‘8-oct-05’ list by p_price;
(c) Select p_code, p_descript, p_indate, p_price
from product order by p_price asc where P_INDATE < ‘8-oct-05’;
(d) Select p_code, p_descript, p_indate,
p_price from product where P_INDATE < ‘8-oct-05’ ascending by p_price;
(e) Select p_code, p_descript, p_indate,
p_price from product where P_INDATE < ‘8-oct-05’order by p_price asc.
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In the above the relation A,B,C,D are the attributes and
(A,B) are the key attributes. The arrows represent the functional
dependencies. Which of the following statements is true based upon the above diagram?
(a)
The above relation has partial dependency (b) The above relation is not in
1NF
(c)
The above relation is not in 2NF
(d) The above relation is in BCNF
(e)
The above relation is in 3NF, but not in BCNF.
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Which of the following structures
eliminates the redundant storage of search key values in B+ trees?
(a)
B-Trees (b)
Indexed sequential file (c) AVL trees
(d)
Hash structure (e)
Graph structure.
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Which of the following is referred to as a sequential
storage device?
(a)
Tape storage (b)
Flash memory
(c)
Optical storage (d)
Cache (e) Main
memory.
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Which of the following statements is false with respect to the storage of the database?
(a) A database is mapped into a number of
different files, which are maintained by the underlying operating system
(b) Each file is partitioned into fixed-length
storage units called blocks
(c) A major goal of database system is to
maximize the number of block transfers between disk and memory
(d) Both (a) and (b) false
(e) Both (b) and (c) false.
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In order to maintain transactional integrity and database
consistency, what technology does a DBMS deploy?
(a)
Triggers (b) Pointers (c) Locks (d) Cursors (e)
Deadlocks.
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A lock that allows concurrent transactions to access
different rows of the same table is known as a
(a)
Database-level lock (b)
Table-level lock
(c)
Page-level lock (d)
Row-level lock
(e)
Field-level lock.
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Which of the following is/are
reason(s) for the existence of variable length records in database systems?
(a) Storage of multiple record types in a file
(b) Record types that allow variable lengths
for one or more fields
(c) Record types that allow repeating fields
(d) All of the above
(e) None of the above.
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Answers
Answer : (d)
Reason
: (d) is the correct option.
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Answer : (b)
Reason
: When there is a primary
key table is said to exhibit entity integrity.
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Answer : (e)
Reason : (e) is the correct syntax for the query.
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Answer : (e)
Reason : A relation
is said to be in BCNF if all the FDs are either trivial or the determinant is
a candidate key. In C→ B, C is not a candidate key. So the relation is not in
BCNF. Since no transitive dependencies are not there and it is in the 2NF the
relation is in 3NF.
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Answer : (a)
Reason : The
redundant storage of search key values in B+ trees is eliminated in B Trees.
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Answer : (a)
Reason
: Tapes are sequential
storage devices.
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Answer : (c)
Reason : Only c
option is false because major
goal of database system is to minimize
the number of block transfers between disk and memory.
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Answer : (c)
Reason
: Locks are used to maintain
database consistency.
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Answer : (d)
Reason
:
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Answer : (d)
Reason
: Variable length records
arise out of all the given reasons.
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