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PROGRAM - BCA
(Revised Fall 2012)
SEMESTER - 3
SUBJECT CODE &
NAME
BCA3020 – Data Base
Management System(DBMS)
CREDIT - 4
BK ID - B1479
MAX. MARKS – 60
Q1. What is data
independence? Briefly explain. [10]
Ans: Data Independence: Data independence is usually
considered from two points of view: physical data independence and logical
data independence. Physical data independence allows changes in the
physical storage devices or organization of the files to be made without
requiring changes in the conceptual view or any of the external views
and hence in the application programs using the database. Thus, the
files may migrate from one type of physical media to another or the file
structure may change without any need
Q2. What is a table
in relational data model? List the properties of relational tables. [10]
Ans: Relational Data Model: The relational model today, is
the primary data model for commercial dataprocessing applications. It
has attained its primary position because of its
simplicity, which eases the job
of the programmer, as compared to earlier data models such as the network model
or the hierarchical model. A database based on the relational model developed
by E.F. Codd allows the
Q3. List and
explain the important responsibilities of database manager. [10]
Ans:
Important responsibilities of database manager: important responsibilities of Database
manager:
·
Interaction
with file manager: The
raw data is stored on the disk using the file system which is usually provided
by a conventional operating system. The database manager translates the various
DML statements into low-level file system commands. Thus the database manager
is responsible
Q4.
Explain the Sequential File Organization with the help of diagrams. [10]
Ans:
Sequential File Organization: A sequential file is
designed for efficient processing of records in sorted order based on
some search-key. A search key is any attribute or set of attributes;
it need not be the primary key, or even a superkey. To permit fast retrieval
of records in search-key order, we chain together records by
Q5. What is view?
List its advantages. [4+6]= 10
Ans:
Views: A view is a virtual table which
does not actually exist. It is made up of a query on other tables in the
database. It could include only certain columns or rows from a table or
from many tables. A view which restricts the user to certain rows is
called a horizontal view, and a vertical view restricts the user to
certain
Q6. Write a note on
the following: 5+5
a) SUBSET Mapping
b) SUPERSET Mapping
Ans: We can see that classes of OOP language can be
mapped to RDBMS tables. For e.g. JAVA classes can be mapped to RDBMS tables. We
can map a persistent class and a table in so many ways. The simplest mapping
between a persistent class and a table is one-to-one. In this case, all
attributes in the persistent class are
Get fully solved assignment. Buy online from website
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we will revert you within 2-3 hour or immediate
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if urgent then call us on 08791490301, 08273413412
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