Database Management System Set 3

Database Management System

Questions 21 to 30

21.	A named set of SQL statements that are considered when a data modification occurs are called (a) Stored procedures (b) Triggers (c) Packages (d) Trapdoors (e) Treatments.
22.	Which protocol ensures conflict serializability? (a) Value based protocol  (b) Read based protocol (c) Timestamp based protocol  (d) Validation based protocol (e) All (a), (b), (c) and (d) above.
23.	Which type of file is easiest to update? (a) Sequential (b) Hashed (c) Indexed (d) Clustered (e) B+ tree.
24.	When a regular entity type contains a multivalued attribute, one must (a) Create a single relation with multiple lines for each instance of the multivalued attribute (b) Create two new relations, one containing the multivalued attribute (c) Create two new relations, both containing the multivalued attribute (d) Crate three new relations (e) None of the above.
25.	Given following figure is an example of mapping which type of relationship? (a) First (b) Second (c) Unary (d) Ternary (e) Binary.
26.	A candidate key must satisfy all of the following conditions EXCEPT (a) The key must uniquely identify the row (b) The key must indicate the row’s position in the table (c) The key must be nonredundant (d) Each nonkey attribute is functionally dependent (e) One of the primary key.
27.	A relation that contains no multivalued attributes and has nonkey attributes solely dependent on the primary key, but contains transitive dependencies is in which normal form? (a) First (b) Second (c) Third (d) Fourth (e) Fifth.
28.	A functional dependency between two or more nonkey attributes is called a (a) Partial functional dependency (b) Partial nonkey dependency (c) Transitive dependency (d) Partial transitive dependency (e) Non transitive dependency.
29.	Which of the following technique is an alternative to log based recovery? (a) Check points (b) Locks (c) Page based (d) Recovery with current transactions (e) Shadow paging.
30.	DBMS periodically suspends all processing and synchronizes its files and journals through the use of (a) Checkpoint facility (b) Backup facility (c) Recovery manager (d) Database change log (e) Shadow paging.

Answers

21.	Answer : (b) Reason:  A named set of SQL statements that are considered when a data modification occurs are called triggers
22.	Answer : (c) Reason:  Timestamp based protocol  ensures conflict serializability.
23.	Answer : (b) Reason:  Hashed file is easiest to update.
24.	Answer : (b) Reason:  When a regular entity type contains a multivalued attribute, one must Create two new relations, one containing the multivalued attribute.
25.	Answer : (d) Reason:  The given mapping is an example of ternary relationship of Patient Treatment with three entities, viz., Patient, Physician and Treatment.
26.	Answer : (b) Reason:  A candidate key (i) must uniquely identify the row                                     (ii)    must indicate the row’s position in the table                                     (iii)   must be non-redundant and (iv)    (iv)     One of the primary key.               A candidate key does not indicate the row’s positon in the table. Hence option (b) is the answer.
27.	Answer : (b) Reason:  A relation that contains no multivalued attributes and has non-key attributes solely dependent on the primary key, but contains transitive dependencies is in second normal form.
28.	Answer : (c) Reason:  A functional dependency between two or more non-key attributes is called a transitive dependency.
29.	Answer : (e) Reason:  Shadow paging technique is an alternative to log based recovery.
30.	Answer : (a) Reason:  DBMS periodically suspends all processing and synchronizes its files and journals through the use of Checkpoint facility.

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