November 1, 2018

Sreekanth B

Baidu Most Frequently Asked Latest Oracle Interview Questions Answers

What Is Oracle 11g?

Oracle 11g is a version of the Oracle Database. The g stands for "grid" to indicate that 11g is "grid-computing ready".

What Is An Extent?

An extent is a specific number of contiguous data blocks, obtained in a single allocation and used to store a specific type of information.

What Is Index Cluster?

A cluster with an index on the cluster key.

What Is Cluster Key?

The related columns of the tables in a cluster are called the cluster key.

How Are The Index Updates?

Indexes are automatically maintained and used by Oracle. Changes to table data are automatically incorporated into all relevant indexes.

What Is An Oracle Index?

An index is an optional structure associated with a table to have direct access to rows, which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.

When A Query Is Sent To The Database And An Index Is Not Being Used, What Type Of Execution Is Taking Place?

A table scan.

What Is The Maximum Number Of Triggers, Can Apply To A Single Table?

12 triggers.

What Is The Output Of Sign Function?

1 for positive value,
0 for Zero,
-1 for Negative value.

What Are The More Common Pseudo-columns?

SYSDATE, USER , UID, CURVAL, NEXTVAL, ROWID, ROWNUM

What Are Pl/sql Cursor Exceptions?
Cursor_Already_Open, Invalid_Cursor

Any Three Pl/sql Exceptions?
Too_many_rows,
No_Data_Found,
Value_Error,
Zero_Error,
Others

To See Current User Name

Sql> show user;
Baidu Most Frequently Asked Latest Oracle Interview Questions Answers
Baidu Most Frequently Asked Latest Oracle Interview Questions Answers

If A View On A Single Base Table Is Manipulated Will The Changes Be Reflected On The Base Table?

If changes are made to the tables and these tables are the base tables of a view, then the changes will be reference on the view.

Can A View Be Updated/inserted/deleted? If Yes - Under What Conditions?

A View can be updated/deleted/inserted if it has only one base table if the view is based on columns from one or more tables then insert, update and delete is not possible.

What Are The Advantages Of View?

- To protect some of the columns of a table from other users.
- To hide complexity of a query.
- To hide complexity of calculations.

What Is Cycle/no Cycle In A Sequence?

CYCLE specifies that the sequence continue to generate values after reaching either maximum or minimum value. After pan-ascending sequence reaches its maximum value, it generates its minimum value. After a descending sequence reaches its minimum, it generates its maximum.

NO CYCLE specifies that the sequence cannot generate more values after reaching its maximum or minimum value.

Which Date Function Returns Number Value?

months_between

Display Odd/ Even Number Of Records

Odd number of records:
select * from emp where (rowid,1) in (select rowid, mod(rownum,2) from emp);
1
3
5

Even number of records:
select * from emp where (rowid,0) in (select rowid, mod(rownum,2) from emp)
2
4
6

To View Installed Oracle Version Information

SQL> select banner from v$version;

Find Out Nth Highest Salary From Emp Table

SELECT DISTINCT (a.sal) FROM EMP A WHERE &N = (SELECT COUNT (DISTINCT (b.sal)) FROM EMP B WHERE a.sal<=b.sal);

Enter value for n: 2
SAL
---------------
3700

Explicit Cursor Attributes

There are four cursor attributes used in Oracle

cursor_name%Found,
cursor_name%NOTFOUND,
cursor_name%ROWCOUNT,
cursor_name%ISOPEN

How Do I Display Row Number With Records?

To achive this use rownum pseudocolumn with query, like
SQL> select rownum, ename from emp;

Output:
-----------------
1 Scott
2 Millor
3 Jiyo
4 Smith

What Is The Difference Of A Left Join And An Inner Join Statement?

A LEFT JOIN will take ALL values from the first declared table and matching values from the second declared table based on the column the join has been declared on. An INNER JOIN will take only matching values from both tables

What Is An Advantage To Using A Stored Procedure As Opposed To Passing An Sql Query From An Application.

A stored procedure is pre-loaded in memory for faster execution. It allows the DBMS control of permissions for security purposes. It also eliminates the need to recompile components when minor changes occur to the database.

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