Chapter wise DBMS

1)What is data?
Ans:Data are known facts that can be reordered and that have implicit meaning.

2)What is database?
Ans:Database is a logical collection of relevant data.It is used for storing,managing and retrieving stored information.

3)What is problem with file based system?
Ans:File involve high level of redundancy.
       Redundancy results in inconsistency.
       It is not amendable to rapid changes
       Many ad hoc queries cant b answered.
       Expensive.
       Modification in one program requires modification in other that may bring about chain of modifications.

4)Explain physical representation of data?
Ans:The smallest unit of data physically stored in database is called stored field and collection of stored field is called stored or physical record. The collection of all occurrence of one type of physical record is called physical file

5)Explain logical representation of data?
Ans:A Logical fiel,record or file is , the field,record or file as it appears to the users,that is, as it is defined in the users application programs.Its structure is different from that of stored records.It also handle system failure so that database can be recovered.

6)What are benefits of database approach?
Ans:
Redundancy can be reduced.
Inconsistency can be avoided.
Data can be shared.
Standards can be enforced.
Security restrictions can be applied.
Integrity can be maintained.
Data independence can be provided.

7) How DBMS works?
Ans:A DBMS provides for storage, updation and retrieval of data in organized manner.

1)User requests data item.
2)DBMS intercepts and interprets the request.
3)Retrieves the data from physical database.
4)Construct the record using physical/conceptual mapping.
5)Record constructed using conceptual/external mapping.
6)Derives the external record from conceptual mapping.


8)What are functions of DBMS?

Data definition:Database allows to define own data in simpler way.
Data manipulation:Database allows to manipulate i.e insert,update and delete information.
Data security and integrity:Database allows us to secure the data and a true picture of data is given to users.
Data recovery and concurrency:If crash occurs , we can go to previously defined consistent data.
Data dictionary:Database maintians meta information in its dictionary.
Performance:Performance of database is maintained irrespective of the load from users.

9)What is Database system?

Users-> application programs --> software to access stored -->software to process------>Stored database
                                                                                                                               ----->Meta data
A DBMS is a complex software that consists of number of modules.It allow communication between various type of users with physical database n operating system , without user being aware of every detail..The DBMS system must maintain information about data i.e stored in system.
The information about data in database is called meta-data.It helps in maintaining effective and efficient database system.

10)What are different kinds of users?