Interview Questions Answers in SQL PLSQL, Oracle General, Database Management

Question { TCS, 24143 }

what is mean by forward declaration and where we'll use it.

Answer

Procedure which allows for Special Sub-program declaration
is nothingbut " Forward Declaration".

Is This Answer Correct ?

3 Yes

0 No

Question { 16462 }

check whether all the emp numbers are indeed unique.

Answer

in rownum we will use < or <= operators only.

If any one knows this query pls send the answer.

Is This Answer Correct ?

0 Yes

1 No

Question { iFlex, 28633 }

what is difference between procedure and function,
procedure and trigger?

Answer

Difference between Procs & Triggers is;

We have control over the firing of Stored Proceudres,
but we don't have control over the firing of Database
Triggers.

Is This Answer Correct ?

12 Yes

3 No

Question { 19937 }

what is explain plan?

Answer

Explain Plan determines the execution plan for SQL
Statements.

Syntax:

expalin paln
set statement_id= ' Text '
schemaname.Table_name@Databaselink
for Statement.

Is This Answer Correct ?

6 Yes

1 No

Question { 34836 }

What is Index and different types of Indexes?

Answer

Index is used to solve some query fast.

we have 2 types of cursors.
1 Bitmap Index ( used only on Low cardinality columns)

2. Btree Index ( used only for High Cardinality of

columns)

Is This Answer Correct ?

8 Yes

18 No

Question { iFlex, 10139 }

diff b/w sub query and co-relater query?

Answer

Sub Query : In this Inner query will execute first. Based
on that result outer query will execute.

Correlated Sub Query : Query which has reference to the
main query , means outer query will execute first based o
that result inner query will execute.

Thank you,
Suresh.

Is This Answer Correct ?

6 Yes

1 No

Question { Wipro, 11997 }

scope of exception handling in plsql

Answer

Raising an error in PL/SQL execution block is nothing
but "Execption". These are of 2 types.
1.Predefined Exception 2. User defined Exception

Total 19+1 predefined exceptions are there.
19+1 means 19+When Others.
"When others" is the last one.After "When Others" no
exception will be raised.
Eg. for Predefined Exceptions:
No_data_found,Dup_val_on_index,Invalid_cursor,Invalid_number
,Zero_Divide,.......,'When Others'..

Thank you,
Suresh.

Is This Answer Correct ?

8 Yes

2 No

Question { Thermotech, 11446 }

What is Highwatermark?

Answer

High Watermark : It's an indicator or Porinter upto which
a Table or Index has ever contained
data .

Is This Answer Correct ?

8 Yes

0 No

Question { Ramco, 19869 }

What is integrity constraints?

Answer

Integrity constraint is a rue that restricts a column of a
table.

Is This Answer Correct ?

19 Yes

14 No

Question { 5022 }

what is the difference between unique and primary key

Answer

Unique Key allows NULL value and a table can have more than
one UNIQUE KEY Constraint.

Primary Key is the combination of UNIQUE+NOT NULL,means it
won't allow NULL Values and a table can have only one
Primary Key.But a table can have Composite Primary Key.

Thank you,
Suresh

Is This Answer Correct ?

4 Yes

0 No

Question { 6060 }

why should required nested tables, Object types, partition
tables and varying arrays. what is the difference between
these are all. give me example with explanation.

Answer

V-Array is an Ordered set of elements.It's having Maximum
size and you can't delete individual elements. V-Arrays are
dense.

Nested Table is an un-orderes set of elements.It doesn't
have maximum size and you can delete individual elements
from Nested Tables . Nested Table can be Parse.

Is This Answer Correct ?

0 Yes

0 No

Question { Oracle, 11671 }

why use cursors?

Answer

Cursor : It's a private SQL worksheet area where we can
execute SQL commands and processing information.
The purpose of the Cursor is, PL/SQL execution block will
process only one records means it will return only one
records.If we want to retrieve or process more number of
records we use the "Cursors".
These are of two types.
1. Implicit Cursor 2. Explicit cursors.

Thank you,
Suresh

Is This Answer Correct ?

30 Yes

1 No

Question { 12922 }

what the meaning of sql

Answer

SQL abbriveated as "Structured Query Language".It is used
to interact with the database.

Is This Answer Correct ?

37 Yes

0 No

Question { Target, 7474 }

Hello All, Could any well write a query for the following
scenario.

Account(table name)
No Name Amount
1 ABCD 2000.00
2 DEFG -2000.00
3 GHIJ 3000.50
4 JKLM 4000.00
5 MNOP 6000.00

O/p Should be in this format
No Name Credit Debit
1 ABCD 2000.00 0
2 DEFG 0 -2000.00
3 GHIJ 3000.50
4 JKLM 0 -4000.00
5 MNOP 6000.00 o

could any one give appropriate query for this
Thnks in Advance
Suneel Reddy

Answer

Select No,Name,to_char(Sal,'$9999.99') amount from emp;

Is This Answer Correct ?

0 Yes

12 No

Question { 21903 }

HOW CAN I FIND MAX SAL ,ENAME FROM EMP TABLE.

Answer

SELECT ename,MAX(sal)
FROM EMP
GROUP BY ename;

Is This Answer Correct ?

9 Yes

15 No

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