11) What Are The Three Types Of Users In DBMS?
Answer: The three types of users in database are:
- END USER who uses the application. They are the one who puts data into the system into use in business.
- APPLICATION PROGRAMMER who develops the application program. They are the one who has more knowledge about the data and structure and can manipulate the data using their programs.
- DATABSE ADMINISTRATOR (DBA) are the super user of the system. They are the one who defines the schema, define security and integrity checks, define backup and recovery procedures and monitor the performance.
12) What Are The Disadvantages Of Database System?
Answer: Some of disadvantages of database system are:
- A high-end processor need to be used in case of DBMS data processing, large memory is required to run the database application, because of which the project cost increases.
- DBMS can be used only for storing a huge amount of data it can’t be used for the simple and small applications for an individual user DBMS is not worthwhile.
- Conversion of legacy data into DBMS data is complex a large amount needs to be spent on the database designer and for the application programmers.
- In most cases all the data is stored in single data base this may get ruined because of some hardware failures on storage device or power failure, then we lose our valuable data.
13) Describe The Three Levels Of Data Abstraction?
Answer: The major purpose of a database system is to provide users with an abstract view of the system. The system hides certain details of how data is stored and created and maintained and thus Complexity should be hidden from database users. There are three levels of abstraction:
- Internal/Physical/Storage level: The lowest level of abstraction describes how data are stored.
- Logical/Conceptual level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data.
- View/External/Individual level: The highest level of abstraction describes only part of entire database.
14) Discuss About External/ View/Individual Level Of The Architecture?
Answer: The external level is the view that the individual user of the database has. This view is often a restricted view of the database and the same database may provide a number of different views for different classes of users. In general, the end users and even the application programmers are only interested in a subset of the database.
For example, a department head may only be interested in the departmental finances and student enrolments but not the library information. The librarian would not be expected to have any interest in the information about academic staff. The payroll office would have no interest in student enrolments.
15) Discuss About Logical/ Conceptual Level Of The Architecture?
Answer: The conceptual view is the information model of the enterprise and contains the view of the whole enterprise without any concern for the physical implementation. This view is normally more stable than the other two views. In a database, it may be desirable to change the internal view to improve performance while there has been no change in the conceptual view of the database.
The conceptual view is the overall community view of the database and it includes all the information that is going to be represented in the database. The conceptual view is defined by the conceptual schema which includes definitions of each of the various types of data.
ALSO CHECK THE BELOW FAQ's:
16) Discuss About Internal/Physical/Storage Level Of The Architecture?
17) What Is Data Independence?
18) What Is Physical Data Independence?
19) What Is Logical Data Independence?
20) What Is A Data Model? What Are The Types Of Data Model?
21) What Is DDL (Data Definition Language), VDL (View Definition Language) and SDL (Storage Definition Language)?
22) What Is Data Storage - Definition Language?
23) What Is DML (Data Manipulation Language) and DML Compiler?
24) What Is DDL Interpreter?
25) What Is Data Model, E-R MODEL & Object Oriented Model?
... Return To HR Interview Questions With Answers Main Page.