Data Base Management Systems-B.C.A 19-22-First-Internal-Exam-FEB-2020

FIRST INTERNAL EXAMINATION, FEBRUARY 2020

Department of Computer Application, Semester II

Database Management Systems

Answer Scheme

Total : 50 marks                                                         Time: 2 hours

Section A

Answer any 5 questions. Each question carries 2 marks.

1.    The database catalog of a database instance consists of metadata in which definitions of database objects such as base tables, views (virtual tables), synonyms, value ranges, indexes, users, and user groups are stored

2.    Create table student(name varchar(2), rollno int,,age int, contactno varchar(20),address varchar(20));

3.    Schema means structure of a database and Instances means content of database at a particular time.

4.    RDBMS-arrange data in row columnwiseeg:SQL,oracle

5.    Insert into tablename values(value1,value2,….)

Delete from tablename where condition;

6.    Primary key is used for uniquely identifying data in a table

Foreign key is used for linking two tables.

7.    A. Self-describing nature of a database

b. Insulation between programs and data

c. Support of multiple views

d. Sharing of data and multiuser transaction processing

8.    Data model:- collection of concepts that can be used to describe structure of a database.

a.     High level datamodel:-It uses concept such as entity,attribute and relationship for describing structure of a database

b.     Logical datamodel-

c.     Lowlevel datamodel- physicat structure such as access path, indexing etc.

9.    DBA

Databse designers

End users-casual users,naïve users

10.  External scheme

Conceptual schema

Internal schema

Draw diagram

11.  Capacity to change the schema at one level without changing higher lavel

1.     Logical data independence:-capacity to change conceptual schema without changing external schema

2.     Physical data independence:- capacity to change physical schema without changing conceptual schema

12.  DDL: create, alter, drop

DML:-Insert, delete, update

13.  Draw picture(5 marks)

Explain different user interfaces

DBA uses DDL commands to define structure of the database and DDL compiler compiles the DDL statements and store result in system catalogue. DBA can also communicate with database using privileged commands.

Casual users communicate database using dml statements, DML compiler convert entered information in to an internal form, precompiler eliminate redundancy and convert the code in to an executable form and give it to runtime database processor.

Runtime database processor works with stored data manager which in turn uses the basic operating system services for carrying out low level input output operations between disk and main memory.

14.  Self-describing nature of a database

b. Insulation between programs and data

c. Support of multiple views

d. Sharing of data and multiuser transaction processing

e. Controlling redundancy

f. provide persistant storage for program object

g. Restricting unauthorized access

h.providing backup and recovery

i. Providing multiple userinterface

j. Representing complex relationship among data