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Courage is not the absence of fear, but rather the judgement that something else is more important than fear.

SQL> begin
2 for i in 1 .. 100 loop
3 i := i + 4;
4 end loop;
5 end;
6 /
i := i + 4;
*
ERROR at line 3:
ORA-06550: line 3, column 5:

As UNION removes duplicate rows, there is a sort involved, adding a
potentially big overhead to the process.

>>what is table mutation error and what is the occation it will happen

Follow the link

“Great dreams of great dreamers are always transcended.” - Abdul Khalam

For wrap utility it is must to sepcify input file name.
wrap iname=/mydir/myfile
Anonymous block is unname block. How can you wrap unnamed block?
I think it is not possible to wrap anlnymouns...

The following link will help you to get basic idea about views
link

SQL> SELECT greatest(12,54,2,75,142) from dual;

GREATEST(12,54,2,75,142)
------------------------
142


Max function takes only one parameter.

SQL> SELECT max(sal)...

Exports & Imports

1.In order to use exp & imp the catexp.sql must be run. It creates exp_full_database and impfull_database roles.

2.Objects owned by sys can't be exported.

3.To see help on...

Coming together is beginning
Keeping together is progress
Working together is success - Henry Ford

When an instance is started, if SPFILE is present, it will be used; otherwise, Oracle searches for a default PFILE.Oracle will scan the files in the following order:

1) spfileSID.ora
2)...

How can we know whether a parameter in parameter file is modifiable or not?


SQL> select distinct issys_modifiable from v$parameter;

ISSYS_MODIFIABLE
—————————
DEFERRED
FALSE
IMMEDIATE

How to know whether database is using pfile or spfile?

sql> select decode(value, null, 'pfile', 'spfile') "parameter file"
2 from sys.v_$parameter where name = 'spfile';

parame
------...

Advantages of SPFILE over PFILE

SPFILEs are available in Oracle 9i and above. All prior releases of Oracle are using PFILEs.

1.An SPFILE can be backed-up with RMAN and PFILE can't.
2.The...

SPFILE and PFILE

SPFILE stands for server parameter file.
Initialisation parameter file init.ora is also called as pfile.

These files hold setup parameters that defines attirbutes of instance....

“Any man who reads too much and uses his own brain too little falls into lazy habits of thinking” – - Albert Einstein

Why are you querying the database in this fashion with scripts that have not been tested ?

>>how to execute a .sql file from a procduer in oracle ?

sql> ed test.sql

delete from emp where empno=7788;

create or replace procedure test_pr as
begin
@test.sql;
commit;

Indexes and between operator

Between operator will consider indexes if there index on a column.
Between is treated as a pair of comparison operators.


sql> select *
2 from emp
...

Indexes and Comparing columns in the same table

Comparing the columns in the same table makes an index useless.



sql> select empno, ename, job, mgr
2 from emp
3 where empno =...

Indexes and Like operator

you can take advantage of an index with like as long as you provide the first character in the pattern.



sql> select ename, job, sal
2 from emp
3 where...

Choosing Between Having and Where

Where puts condition on the table rows.
Having puts condition on grouped results.

The processing order is as follows.
1. Select rows with WHERE
2. Divide...

Control File Related Views

V$CONTROL FILE :- This view lists the names of the control files.



SQL> SELECT name
2 FROM v$controlfile;

NAME

Dynamic performanc views - IV

V$BGPROCESS :- This process describes the background processes.

V$BH:- This is a parallel server view. This view gives the status and number of pings for every...

Dynamic performanc views - III

V$instance :- It displays information of the current instance.



SQL> SELECT instance_name,
2 version,
3 status,
4...