Skip to main content

Could not update my site

Hi ALL,

Had a very hard time last week, my phone crashed, my laptop hardisk crashed and was loaded with work.

For this reason I was not able to reply to anyone's comments or update my site with latest information. I should be able to do this in a day or two as I have got hold of a spare laptop. Still waiting for the data from my old hard disk to be recovered.

Mithun
Labels:

Comments

ABHISHEK ANAND said…
sir,
can you explain once the difference between master and child table.
September 4, 2011 at 8:01 PM
Mithun Ashok said…
Hi Abhishek,

If a table has a foreign key from another table then this table is called as Child table and the table which is referred is called as Master table.

Regards,
Mithun
September 4, 2011 at 9:23 PM
niharika said…
hi sir
wish u a very happy teacher's day.......
September 5, 2011 at 6:12 PM
Mithun Ashok said…
Hi Niharika,

Thank you for your wishes.

:-)
Mithun
September 10, 2011 at 7:46 AM
Anonymous said…
sir m a bce2 batch student as manual is gng on and v r giving presentations m not able to do sql properly...will it b fine if i give 1 whole sunday for sql?will i b able to make it 4 interviews?sir u hav teached us splendidly and m feeling m loosing d grip nw...
October 13, 2011 at 1:45 PM
Mithun Ashok said…
Hi Anonymous,

As long as you are practicing it does not matter if you are working only on sunday or any other day. I would suggest you to brush through the concepts on a regular basis atleast once in 2 days, And practice sql hands on.

Regards,
Mithun
October 14, 2011 at 7:41 AM
Post a Comment

Popular posts from this blog

SQL Interview Questions on Subqueries

SUB Queries:
1. List the employees working in research department 2. List employees who are located in New York and Chicago
3. Display the department name in which ANALYSTS are working
4. Display employees who are reporting to JONES
5. Display all the employees who are reporting to Jones Manager
6. Display all the managers in SALES and ACCOUNTING department
7. Display all the employee names in Research and Sales Department who are having at least 1 person reporting to them
8. Display all employees who do not have any reportees
9. List employees who are having at least 2 reporting
10. List the department names which are having more than 5 employees
11. List department name having at-least 3 salesman
12. List employees from research and accounting having at-least 2 reporting
13. Display second max salary
14. Display 4th max salary
15. Display 5th max salary  -- Answer for nth Max Salary
Co-Related Subqueries:
16. Write a query to get 4th max salary from EMP table
17. Write a query to get 2nd…
21 comments
Read more

'Linux-x86_64 Error: 28: No space left on device' While trying to start the database -- Error

SQL> startup mount pfile='/tmp/initdlfasp12.ora'
ORA-27102: out of memory
Linux-x86_64 Error: 28: No space left on device


This as you can see is on Linux x86 with 64 bit processor. We got this error after we changed SGA on 10gR2 database. So was sure that this is something to do with the OS.

Parameters to check for this are shmall.

shmall is the total amount of shared memory, in pages, that the system can use at one time.

$cat /proc/sys/kernel/shmmax
53687091200

$ getconf PAGE_SIZE
4096

As per Oracle SHMALL should be set to the total amount of physical RAM divided by page size.

Our system has 64GB memory, so change kernel.shmall = 1024 * 1024 * 1024 * 64 / 4096 = 16777216


Once this value is calculated you can modify Linux system configuration file directly.

$ su - root
vi /etc/sysctl.conf file:
kernel.shmall=16777216

and

# sysctl -p

Once this is done the database was started without any problem.
14 comments
Read more

Answers for SUB Queries

1. SQL> select empno, ename from emp where deptno=(select deptno from dept where dname='RESEARCH');


2. SQL> select empno, ename from emp where deptno in (select deptno from dept where loc in ('NEW YORK','CHICAGO'));

3. SQL> select dname from dept where deptno in ( select deptno from emp where job ='ANALYST');

4. SQL> select empno, ename, mgr from emp where mgr = (select empno from emp where ename='JONES');

5. SQL> select empno, ename, mgr from emp where mgr = (select mgr from emp where ename='JONES')

6. SQL> select empno, ename, job from emp where deptno in ( select deptno from dept where dname in ('SALES','ACCOUNTING'))

7. SQL> select empno, ename, job from emp where deptno in ( select deptno from dept where dname in ('SALES','RESEARCH')) and empno in (select mgr from emp)

8. SQL> select empno, ename from emp where empno not in ( select mgr from emp where mgr is not null)

9. select…
8 comments
Read more