Databases Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

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Databases Interview Questions

Questions Answers Views Company eMail

In my table i have 4 columns with 100 records but in that 4 columns one column contains all NULL values so can i add NOT NULL CONSTRAINT on that column......... ok if it is not possible, can i add NOT NULL CONSTRAINT from 101 Record Onwards?

Cap Gemini,

4 8370

How many null values can be inserted in a coulmn whihc is unique constraint

Flextronics,

8 13476

How is Oracle 10g helpful when compared to oracle 9i and what is grid computing

Flextronics,

1 5616

I want to insert userid of a customer,order time,etc in a table called ordermaster with orderid as primary key.Same time the product codes and required quantities (a1,2 and a2 4 and so on)inserted in another table orderdetails with same orderid reference.How the code will be in JSP using MySQL?

1972

* CREATE TABLE [dbo].[t_Colors]([ColorId] [int] NOT NULL,[ColorName] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [ColorDesc] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,[ColorIndex] [int] NULL) ON [PRIMARY] GO * insert into [t_Colors] values(101,'Red','',1) insert into [t_Colors] values(101,'Red1','',2) insert into [t_Colors] values(102,'Blue','',1) insert into [t_Colors] values(102,'Blue1','',2) insert into [t_Colors] values(102,'Blue2','',3) * In this table i need to delete DELETE FROM t_Colors WHERE ColorIndex=1 AND ColorId=102 After delete above condition i need to update the ColorIndex set to 1 for Blue1[ColorName] and 2 for Blue2[ColorName] select * from [t_Colors] Note:- how can i get updates the ColorIndex values after delete. for example we need to update Blue1 ColorIndex set to 1 and Blue2 ColorIndex set to 2

1943

wat wil hapn if we give the both read and deny read permission to user?

IBM,

2154

in my server i have 3 instances,one of them got failed, and this cause we r not able to connect to server, how to know which instance was dameged?

IBM,

1 4641

What is difference between stored procedure and function?

L&T,

3 7786

i have account table which consists of account name,card no and card no consists 16 digits now i want to retrieve the data if card no starts from 4 then it should print visa and if it starts from 5 then it should print master so plse help me to write simple query with out store procs .

3 5143

How to select top 5 coloumn from a table without using coloumn name

5 8101

What is the difference between SQL and PLSQL

IBM,

7 11469

the user should know to which database he is connected currently in oracle

3 4750

What is the difference between primary and unique key

CSC,

5 8434

what is the use of database index(apart from the last searching of records) and what is the use of composite key?

1 3766

query to retrive the employees whose sal is greater than avg sal

TCS,

10 15548

Un-Answered Questions { Databases }

What is composite foreign key?

797

What is the difference between truncate and delete? Why is one faster?

701

What are pl sql procedures?

1082

How is super key different from a candidate key?

951

Where is the quick access toolbar located?

1027

Why is the use of dbms recommended?

1327

Explain various data region available in ssrs with their use?

989

Explain force logging feature in 9i.

654

Which parameters are optional in init.ora parameter file?

2279

What is the sql server agent?

1148

What is the use of lockboxes? Steps for lock box : oracle accounts receivable

1484

What is the main difference between sql and pl/sql?

1151

What is the meaning of sql server?

1041

Differentiate between syntax and runtime errors.

1242

Enlist some commands of ddl?

1011

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