What are RAID levels 0/1/5/10?

Level	Minimum Disk Req.	Performance	Redundancy	Suggestions
0	2	Excellent	None	Not recommended for critical systems
1	2	Good	Excellent
5	3	Good	Good	Best cost effective option providing both performance and redundancy. Use this for DB that is heavily read oriented. Write operations will be slow.
10	4	Excellent	Excellent	If you can afford the dollar, this is the BEST option for any mission critical applications (especially databases).

Ref: http://www.thegeekstuff.com/2010/08/raid-levels-tutorial/

What is Oracle doing when you run commit?

The basic flow like that;

1. Oracle writes that "Commit has been executed" in related table from UNDO tablespace. 
2. SGA buffer cache - calling LGWR (Log Writer)
3. LGWR writes changed data (delta) to REDO log files
4. Tables' locks are released and marked as "TRANSACTION is completed" by Oracle

How to use Intersect function?

For instance, you want to see same jobs for employees that belong to different manager in employees table.

Please run the sql lines in SQL Editor as "hr" user;

SELECT job_id FROM employees
WHERE manager_id = 121
INTERSECT
SELECT job_id FROM employees
WHERE manager_id  = 122;

Used Database User: HR

Linux date function examples

e.g.
date -d now
date -d today
date -d yesterday
date -d mon
date -d tue
date -d wed
date -d thu
date -d fri
date -d sat
date -d sun
date --date="1 day ago"
date --date="1 week ago"
date --date="1 month ago"
date --date="1 year ago"
date -d "+10 days"
date -d "+10 weeks"
date -d "+10 months"
date -d "+10 years"

[CONCAT] How to merge two strings as a single string?

Please run the sql lines in SQL Editor as "hr" user;

e.g.
select CONCAT('Bilgi havuzu ','at ozsoyler.blogspot.com') from dual;
result
Bilgi havuzu at ozsoyler.blogspot.com

Used database user: hr
Used database server: oracle xe

[INITCAP] How to make uppercase the first character of each word in a string?

Please run the sql lines in SQL Editor as "hr" user;

e.g.
select INITCAP('ozsoyler.blogspot.com') from dual;
result
ozsoyler.Blogspot.Com

Used database user: hr
Used database server: oracle xe

[ADVICE] Free Windows Disk Defragmenter Alternative

I strongly recommend to use Smart Defrag tool instead of classical Windows Defragmenter tool.

How to check NTFS file system in CMD?

Only you need to run this command.

e.g. chkntfs C:

C:\Windows\system32>chkntfs C:
The type of the file system is NTFS.
C: is not dirty.

How to defrag disk partiton in CMD?

Only you need to run this command as Administrator.

e.g. defrag C:

How to change font color in CMD?

Only you need to run this command in cmd.

e.g. color A

0 = Black
1 = Blue
2 = Green
3 = Aqua
4 = Red
5 = Purple
6 = Yellow
7 = White
8 = Gray
9 = Light Blue
A = Light Green
B = Light Aqua
C = Light Red
D = Light Purple
E = Light Yellow
F = Bright White

How to define a tablespace in Windows?

Please execute the commands as "sys";

To define the tablespace:
SQL> CREATE TABLESPACE ALPER_DATA 
DATAFILE 'C:\tablespaces\data_01.dbf' SIZE 128M

To alter the tablespace:
SQL> ALTER TABLESPACE ALPER_DATA ADD DATAFILE 'C:\tablespaces\data_new_02.dbf' size 128m;

To drop the datafile from the tablespace:
SQL> ALTER TABLESPACE ALPER_DATA DROP DATAFILE 'C:\tablespaces\data_new_02.dbf';

To drop the tablespace:
SQL> DROP TABLESPACE ALPER_DATA 
INCLUDING CONTENTS AND DATAFILES;

To check tablespace's database files:
SQL> SELECT NAME, FILE#, STATUS FROM V$DATAFILE;

Used Oracle Version and OS: Oracle XE and Win7

How to prepare a video with steps via windows tool?

Please you run this command first in cmd.

CMD> psr

Then you can record the steps by clicking start record.

After finish your video, you are able to check .mht file by extracting zip file.

How to know hostname from IP in Command Prompt?

Press Windows button + R and press cmd then click "OK".
Then, write down "below command" and press enter

nbtstat -a <IP>
e.g. nbtstat -a 10.10.10.10

How to delete linux user?

# sudo userdel -r alper

-r -> Remove home directory and mail spool

How to run sql query in shell script?

Please add these codes into your .sh file then you can run .sh file

e.g. 
ssh -q -T oracle@192.168.2.2 << EOF
sqlplus / as sysdba << EOFSQL
drop user ALPER_DB_USER cascade;
exit;
EOFSQL
EOF

How to know file format description in CMD?

Please you run this command in CMD.

e.g. assoc .rar
.rar=WinRAR

e.g. assoc .txt
.txt=txtfile

What are testing types and methods?

There are two test methods which are Black Box Testing and White Box Testing

Basically, there are two test types which are Functional and Non-functional.

For example, White & Black Box (Mostly), Unit, Interface & Usability, System, Regression and User Acceptance testing are Functional testing types.

Likewise, Load & Performance, Stress, Installation and Compatibility & Migration testing are Non-functional testing types.

White & Black Box Testing

White Box Testing (we know codes and are able to debug testing in codes)

Black Box Testing (we do not know codes and act as a customer)

Black Box Testing Types & Methods

• Equivalence partitioning (keyword is clustering)
• Boundary Value Analysis (keyword is looking boundary conditions)
• Cause Effect Graphing (keyword is causes -> intermediate nodes -> effects and reduced decision table)

What is the goal of testing?

The goal of testing is to reach minimum bug number and using time effectively as person/day.

What are Verification and Validation in software world?

Verification is that the process of evaluating work-products (not the actual final product) of a development phase to determine whether they meet the specified requirements for that phase.

Activity of Verification: Reviews, Walkthroughs and Inspections

Question: Are we building the product right?

Validation is that the process of evaluating software during or at the end of the development process to determine whether it satisfies specified business requirements.

Activity of Validation: Testing

Question: Are we building the right product?

Ref: http://softwaretestingfundamentals.com/verification-vs-validation/

How to know SuSE release version?

Only run this command in terminal;

$ cat /etc/SuSE-release
or
$ cat -n /etc/SuSE-release
(-n) to see rows numbers as well