CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
SMUAPR15
ASSESSMENT_CODE MI0034_SMUAPR15
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
204985
QUESTION_TEXT
a. Describe how to place records on the disk.
b. What are the various operations that can be done on files? Explain
the two different types of records.
a.
The different types of record types are
Fixed length records and variable length records, most of the file may have
variable length records for various reasons such as recording having
variable length fields, having repeating fields, having optional fields,
record blocking and spanned versus un–spanned records.
Allocating file blocks on Disks:
File headers contains information about a file that is needed by the
header and includes information to determine the disk addresses of the
file blocks as well as to record format descriptions.
5 marks
SCHEME OF
EVALUATION
b. Operations are insertion, deletion and modification. The commands
used are Find, read, find next, delete, modify and insert
There are two types of records: files of unordered records and files of
ordered records.
Searching algorithm for sequential and unordered files, they are
sequential search, binary search, hashing technique.
In hashing technique, key value to convert to hash function that provides
fast access to records. The basic terminologies associated with hashing
techniques are Hash table, Hash function and Hash key.
5 marks
(Total 10 Marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
204986
QUESTION_TEXT
a. Consider two relations S and T and perform the following set
theoretic operations with an example for any Three.
i.
S∪T Relation
ii. S∩T Relation
iii. S–T Relation
iv. S×T Relation
b. List all the relational operation with an example.
a.
Consider S table and T table with values inside
i.
ST Relation with values
1 mark
ii.
S∩T Relation with values
1 mark
iii.
S–T Relation with values
1 mark
iv.
SCHEME OF
EVALUATION
SXT Relation with values
2 marks
b.
SELECT
PROJECT
2 marks
JOIN operations
theta join, equi join, natural join, outer join, and so on.
3 marks
(Total 10 Marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
204987
QUESTION_TEXT
Describe the transaction processing concepts.
A transaction is an atomic unit comprising one or more SQL
statements. A transaction begins with the first executable statement
and ends when it is committed or rolled back.
Single user versus multiuser systems – A DBMS is used if at most
one user can use the system at a time. It is multiuser if many users
can use the system and have access to the database concurrently.
A transaction is a logical unit of database processing that includes
one or more database access operations (insertion, delete, etc). Only
retrieval of data is called read–only transaction.
The basic database access operations are as follows:
1.
Read–item (x)  It reads a database item named “x” into a
program variable.
2.
Write–item (x)  It writes the value of the program variable x
into the database.
SCHEME OF
EVALUATION
•
Concurrent control – The data in the database must perform
their transactions concurrently without violating the ACID
(Atomicity, Consistency, Integrity and Durability) properties of a
database.
•
Need for concurrency control – In a multiuser database,
transactions submitted by the various users may execute
concurrently and update the same data.
•
Data concurrency – Access to data concurrently
(simultaneously) used by many users must be coordinates.
•
Data consistency – A user always sees a consistent (accurate)
view of all data committed by other transactions as of that time and
all changes made by the user up to that time.
The types of problems we may encounter when these two
transactions run concurrently.
1. The lost update problem –
2. Dirty read problem
3. Incorrect summary problem
10 marks
(Total 10 Marks)
QUESTION_T
DESCRIPTIVE_QUESTION
YPE
QUESTION_I
204988
D
QUESTION_T Explain the overview of distributed database management system, and also
EXT
make a comparison with centralized database systems.
As a general goal, distributed computing systems divide a big,
unmanageable problem into smaller pieces and solve it efficiently in a
coordinated manner
Functions of distributed databases
Basic functions performed by DDBMS in addition to those of centralised
DBMS are Distributed query processing, Data tracing, Distributed
transaction management , Distributed database recovery , Security,
Distributed directory (catalogue) management
(5 marks)
Differences between distributed database and centralised database (5
marks)
SCHEME OF
EVALUATIO
N
(Total 10 Marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
204989
a.
Explain the different mapping cardinalities with an example.
b.
Write short note on degree of relationship.
QUESTION_TEXT
a. The different mapping cardinalities are of four types. They are
as follows:
SCHEME OF
EVALUATION
•
One–to–one
•
One–to–many
•
Many–to–one
•
Many–to–many
5 marks
b. Degree of relationship type is the number of entity sets that
participate in a relationship set. A unary relationship exists when an
association is maintained with a single entity. A binary relationship
exists when two entities are associated. A ternary relationship exists
when there are three entities associated
5 marks
(Total 10 Marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
204990
QUESTION_TEXT
SCHEME OF
EVALUATION
Describe the locking techniques for concurrency control.
Several types of locks are used in concurrency control to introduce locking
concepts gradually. Some of the locks are binary locks, which are simple
but restrictive and therefore not used in practice, shared locks and
exclusive locks, which provide more general locking capabilities and are
used in practical database locking schemes. Two–phase locking protocol
and Strict two–phase locking are the techniques used. Deadlock and
starvation– In deadlock state, there exists a set of transactions in which
every transaction in the set is waiting for another transaction in the set.
10 marks
(Total 10 Marks)