RDBMS Interview questions

RDBMS Concepts 
1. What is database? 
A database is a logically coherent collection of data with some inherent meaning, representing some aspect of real world and which is designed, built and populated with data for a specific purpose. 
 
2. What is DBMS? 
It is a collection of programs that enables user to create and maintain a database. In other words it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the database for various applications. 
 
3. What is a Database system? 
The database and DBMS software together is called as Database system. 
 
4. Advantages of DBMS? 
? Redundancy is controlled. 
? Unauthorised access is restricted. 
? Providing multiple user interfaces. 
? Enforcing integrity constraints. 
? Providing backup and recovery. 
 
5. Disadvantage in File Processing System? 
? Data redundancy & inconsistency. 
? Difficult in accessing data. 
? Data isolation. 
? Data integrity. 
? Concurrent access is not possible.  
? Security Problems. 
 
6. Describe the three levels of data abstraction? 
The are three levels of abstraction: 
? Physical level: The lowest level of abstraction describes how data are stored. 
? Logical level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data.  
? View level: The highest level of abstraction describes only part of entire database.

 
7. Define the "integrity rules" 
There are two Integrity rules. 
? Entity Integrity: States that "Primary key cannot have NULL value" 
? Referential Integrity: States that "Foreign Key can be either a NULL value or should be Primary Key value of other relation. 
 
8. What is extension and intension? 
Extension -  
It is the number of tuples present in a table at any instance. This is time dependent. 
Intension -  
It is a constant value that gives the name, structure of table and the constraints laid on it. 
 
9. What is System R? What are its two major subsystems? 
System R was designed and developed over a period of 1974-79 at IBM San Jose Research Center. It is a prototype and its purpose was to demonstrate that it is possible to build a Relational System that can be used in a real life environment to solve real life problems, with performance at least comparable to that of existing system.  
Its two subsystems are  
? Research Storage  
? System Relational Data System. 
 
10. How is the data structure of System R different from the relational structure?  
Unlike Relational systems in System R  
? Domains are not supported 
? Enforcement of candidate key uniqueness is optional 
? Enforcement of entity integrity is optional 
? Referential integrity is not enforced 
 
11. What is Data Independence? 
Data independence means that "the application is independent of the storage structure and access strategy of data". In other words, The ability to modify the schema definition in one level should not affect the schema definition in the next higher level. 
Two types of Data Independence: 
? Physical Data Independence: Modification in physical level should not affect the logical level.  
? Logical Data Independence: Modification in logical level should affect the view level.  
NOTE: Logical Data Independence is more difficult to achieve 
 
12. What is a view? How it is related to data independence? 
A view may be thought of as a virtual table, that is, a table that does not really exist in its own right but is instead derived from one or more underlying base table. In other words, there is no stored file that direct represents the view instead a definition of view is stored in data dictionary. 
Growth and restructuring of base tables is not reflected in views. Thus the view can insulate users from the effects of restructuring and growth in the database. Hence accounts for logical data independence. 
 
13. What is Data Model? 
A collection of conceptual tools for describing data, data relationships data semantics and constraints.


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Interview questions.

Every Organisation needs smart and hardworking people among all the others persons. I have confident that i am one of the person in those who are having good ideas and willing to work harder. this makes u hire me.

I will always give my best whatever the job i am working on. You can expect 100% effort from my side. 

Yes sir, i have successfully completed 3 rounds so far, from this i am clear that i have all the qualities that your company looks for. moreover i have a very good communication skills, programming skills

So let me first say my strength i am quick learner, dedicated person and young man with lot of dreams. And most importantly i never hate reading new things, so i think this will fit me for any company

I think my profile suits the job requirements,and I also i do give my best to the concern

What are your strengths and weaknesses?

My strength is hard work, think positively, confidence. Weakness is my lazyness, feeling shy, emotional angry.

Why do you want to work at our company?

Because our company is one of the top most company

Because our company is most famous leading in all over world so that's why I choose this company and also help to develop my communication skills.

What is the difference between confidence and over confidence?

In my point of you confidence is a first step in our life. 
"I can do"is a confidence. 
"No one can do better than me"is a over confidence

"I KNOW" it is confidence, 
"I ONLY KNOW" That is overconfidence

What is the difference between hard work and smart work?

Hard work is too important in our life to learn everything to work on that to reach your goal 
and smart work is quality of work what is we need in work

Hard work refers the work which is done sincerely and by working hard. Smart work refers that completing the work in a short period of time effectively .

Smart work comes from Hard Work.It is the next step of Hard Work.

How do you feel about working nights and weekends?

Depends on the need of project that will be always ok.

Can you work under pressure?

ya i can but i don't like to get that type of situation in work

No, because under pressure some times we done so many mistakes... so normally we can do easy and finish my work...

yes, but not regularly it makes mind always tension in all ways & to make wrong desisons too.

What are your goals?

I want a good position in our society and make all of them as happy.

My final goal is to lookafter my parents, if stay in any job.

How long would you expect to work for us if hired?

I'm lookin for a long term career in u r organization

as long as the company needs my service

I want to join in MBA.

Tell me something about our company.

IBM is a fast growing company in IT & it's good for a fresher bec. they can prove thereself in this company everyone know's the name of IBM .it's big international company

How much salary do you expect?

I think that is depend on my qualification, my performance & my hard work.

As per the company norms.............

Where do you see yourself five years from now?

May be a successful business man

I am in good position in your company

On a scale of one to ten, rate me as an interviewer.

sir im not having experience to rate you,but you are correct person as an interviewer

sir i am not in such position to rate you. 
but only i can say as an interviewer you are very much friendly & having very good communication skill

Sir i'm hoping that you are interviewing so many persons so i am hoping that you are a good knowledge person so i think 10 out of 10...

Do you have any questions for me?

What is your opinion on me.?

Are You get Satisfied with my answers ?

am i the right person for the company ? 
 

Patni Placement Question Paper(sample)

Q1). The length of rectangle is increased by 15% and its breadth is decreased by 15%. The are of new rectangle is

a) Decreased by 15%
b) Decreased by 2.25%
c) Increased by 15%
d) Increased by 2.25%
e) Neither increased nor decreased

Q2). Two trains are running at 60 km/hr and 40 km/hr in the same direction. Fast train completely passes the man sitting in the slow train in 36 seconds. The length of the fast train is

a) 200m
b) 160m
c) 240m
d) 180m
e) Cannot be determined

Q3). A,B and C can complete a piece of work in 10 days, then how many people are required to finish the whole work in 25 days?

a) 10 days
b) 15 days
c) 20 days
d) 22 days
e) 25 days

Q4). 12 persons can do 3/5 of certain work in 10 days, then how many persons are required to complete the whole work in 25 days?

a) 10
b) 9
c) 8
d) 7
e) 6

Q5). In an organization, 30% of the employees are matriculates, 60% of the remaining are graduates and the remaining 140 are post-graduates. How many employees are graduates?

a) 210
b) 280
c) 350
d) 160
e) None of these

Q6). If x: y = 3:4, then (2x+3y): (3y-2x) =

a) 2:1
b) 4:1
c) 3:2
d) 5:3
e) 3:1

Q7). A mixture of 50 litres of milk and water contain 10% of water. How much water must be added to make water 20% in the given mixture?

a) 5.5 litres
b) 6.5 litres
c) 6 litres
d) 6.25 litres
e) 6.75 litres

Q8). A dealer marks his goods 25% above cost price. He then allows some discount on it and makes a profit of 9%. The rate of discount is

a) 11.4%
b) 12.8%
c) 13.4%
d) 14.2%
e) 15.1%

Q9). A number lying between 1000 and 2000 is such that on division by 2,3,4,5,6,7 and 8 leaves remainders 1,2,3,4,5,6 and 7 respectively. The number is

a) 1726
b) 1822
c) 1548
d) 1922
e) 1679

Q10). Three years ago the average of a family of 5 members was 17 years. A baby having born in between, the average age of the family is same today. When was the baby born?

a) 1 year ago
b) 2 years ago
c) 3 years ago
d) just today
e) none of the above

Q11). The sum of the digits of a two-digit number is 9 less than the number. Which of the following digits is at unit's place of the number?

a) 1
b) 2
c) 4
d) 8
e) None

Q12). One year ago, Mrs kusuma was four time as old as her daughter Swathi. Six years hence, Mrs. Kusuma's age will exceed her daughters age by 18 years. The ration of present ages of Kusuma and Swathi is

a) 25:7
b) 13:4
c) 25:9
d) 13:1
e) None of these

Q13). The calendar for year 1994 will serve as calendar for

a) 1998
b) 2002
c) 2003
d) 2004
e) 2005

Q14). The minute hand of clock overtakes the hour hand at intervals of 63 minutes of correct time. How much a day does the clock gain or loose?

a) Gains 10 10/43 minutes
b) Gains 56 8/77 minutes
c) Loses 10 10/43 minutes
d) Loses 56 8/77 minutes
e) None of these

Q15). The expression (11.98 * 11.98 + 11.98 * X + 0.02 * 0.02 ) will be a perfect square for X equal to:

a) 0.01
b) 0.02
c) 0.03
d) 0.04
e) 0.05