Difference between VARCHAR and VARCHAR2?

varchar means fixed length character data(size) ie., min size-1 and max-2000
where as varchar2 means variable length character data ie., min-1 to max-4000

NOT EXISTS vs NOT IN......in DB2

Well, the two are processed very very differently.

Select * from T1 where x in ( select y from T2 )

is typically processed as:

select * 
  from t1, ( select distinct y from t2 ) t2
 where t1.x = t2.y;

The subquery is evaluated, distinct'ed, indexed (or hashed or sorted) and then joined to 
the original table -- typically.


As opposed to 

select * from t1 where exists ( select null from t2 where y = x )

That is processed more like:


   for x in ( select * from t1 )
   loop
      if ( exists ( select null from t2 where y = x.x )
      then 
         OUTPUT THE RECORD
      end if
   end loop

It always results in a full scan of T1 whereas the first query can make use of an index 
on T1(x).


So, when is where exists appropriate and in appropriate?

Lets say the result of the subquery
    ( select y from T2 )

is "huge" and takes a long time.  But the table T1 is relatively small and executing ( 
select null from t2 where y = x.x ) is very very fast (nice index on t2(y)).  Then the 
exists will be faster as the time to full scan T1 and do the index probe into T2 could be 
less then the time to simply full scan T2 to build the subquery we need to distinct on.


Lets say the result of the subquery is small -- then IN is typicaly more appropriate.


If both the subquery and the outer table are huge -- either might work as well as the 
other -- depends on the indexes and other factors.

About Agile terminology

Scrum is perhaps one of the simpler project management methods to learn and implement. In this guide, I will show you how to speak the language of Scrum and utilize this valuable management tool for your company.

Basic Scrum Vocabulary
Before being able to implement Scrum, it is important to be familiar with some key words in the the Scrum vocabulary.

Sprint- a 30-day focused effort moving the team toward fixed goals.

Product Backlog- a constantly prioritized to-do list.

Sprint Backlog- a list of the highest prioritized items from the product backlog.

Scrum Master- the coach for the product management team and works to ensure the realization of the goals of the sprint.

Product Owner- represents the customer and is responsible for prioritizing the backlog.

Scrum Team- a group of 5-9 people who self-organize and have joint responsibility for the completed tasks.

The Scrum Process
Now that basic vocabulary related to Scrum has been defined I will detail the Scrum process step-by-step.

1. Creating a backlog – in this step, the Product Owner and Scrum Team meet in order to discuss the priority and items on the Product Backlog. The Product Owner must be able to form the product vision. The Product Backlog then, is a prioritized list of what is required for the project and is ranked with regard to importance.

2. Once the product manager creates the backlog, then there will be a Sprint Planning Meeting. During the first phase of the meeting, the Product Manager describes to the team the goals of the project and explains the Product Backlog. During the second phase, the Scrum Team will select the items to be completed during the sprint from those with highest priority on the Product Backlog.

3. Once the items to be worked on have been selected, a potential Sprint schedule is constructed – taking into account the availability of the team members to devote their time to the project. The items in the Product Backlog are assigned and broken down into individual tasks. Once this occurs, this document is the Sprint Backlog.

4. The Sprint begins and lasts from 15-30 days. During the Sprint, no other tasks are added to the backlog.

5. Daily Scrum begins when the sprint begins. The Daily Scrum is a 15 minute stand-up meeting where each member of the team gives a very brief report to everyone else – what they accomplished since the last Daily Scrum, what they hope to accomplish, and issues that have come up. Here, the Scrum Master will make note of issues and attempt to resolve them – after the meeting.

6. Sprint Review – once the Sprint ends, everyone gets together in a meeting to share what he or she accomplished during the sprint.

7. The process begins again with a new list of prioritized tasks on the Product Backlog.

While this is a very brief overview of the Scrum process, there is enough information here in order to begin implementing Scrum in your own company. The only templates for running projects with scrum is Product BackLog and Sprint BackLog. You can plan resources, time and estimations of individual items from the Product BackLog with Microsoft Project or other planning tool.

Kavita

Few lines written by me :-


1) Meri Samvedna Ko Himakat Samajh Baithe Woh,

    Mere Kiye Hue Prashno Ko Kataksh Samajh Baithe Woh,

    Saath Thay Hum Hamesha Par Khud Ko Akela Samajh Baithe Woh...

2) Mere Hazrat Ki Barkat Saath De Gayi,

    Iss Baar Bhi Baarish Bahut Tez Thi, Gharonday Mein Rakhe Thay Bartan Aur Roti Apne Naseeb Ki

    Haath De Gayi....

3) Pratibimb Ki Pratidhavani Ko Maapne Ki Koshish Kar Raha Tha,
    Hatheli Se Suraj Ki Lalima Chunay Ki Koshish Kar Raha Tha,
    Mann Ke Hanan Ka Karan Ye Tha Ki Main Vaastvikta Chod Parikalpana Mein Jeenay Ki Koshish Kar
    Raha Tha....


4) Parhez Nahin Mujhe Uske Naam Se,

    Par Kabhi Qatil Na Kehlau Iss Baat Se Darta Hu...

5) Bin Mullah Koun 'Peer' Hoye Bhala,
    Aji Yeh Rang Nahin Khoon Ki Taaseer Hi Hai Kalah...


6) Pratikulta Mein Anukulta Ka Anubhav Kar Raha Hu,
    Vishaye Se Durr Honay Par Bhi Saar Chu Raha Hu,
    Ye Uss Neelvarn Ki Abha Hai ki Vilom Mein Bhi Lom Ko Dhoond Raha Hu....


7) Aashiqo Ki Mazaar Pe Zara Jam Ke Rakhna Kadam,

    Yahan Wazzu Kare Bina Hi Khuda Deekh Jaate Hai...

8) Shikayat Nahin Khud Pe Afsoos Aata Hai,

    Durr Hai Sahil Aur Falak Paas Nazar Aata Hai,

    Ye Ghutan, Ye Badhawasi Ka Aalam,

    Mere Paimaanay Mein Zayada Aur Uske Paas Kum Kyu Nazar Aata Hai...

9)  This Kavita is about 'Yamuna Ji' ....This was written when Yamuna was roaring high during Aug,2010 in Delhi....


  Aansu Se Bhar Ke Hi Dhul Jaungi Main....


   Kal  Tak Nirjeev Samajh Ke Choda Tha Mujh Ko,
   Kal  Tak Nirjeev Samajh Ke Choda Tha Mujh Ko,
   Aaj Apna Prachand Vaig Dekhlaungi Main....


   Bharsak Prayaas Kiya Tum Ne,
   Bharsak Prayaas Kiya Tum Ne,
   Mere Muhaanay Ko Badalne Ka,
   Aaj Apne Asli Astitv Ko Vistaar Mein Laaungi Main...


  Bahut Piya, Bahut Piya,
  Yamuna Ji, Yamuna Ji, Sunn Sunn Ke Apmaan,
  Main Bhi Hoon 'Yum' Ki Behen, Ye Sabko Yaad Dilaungi Main...


  Ye Sabko Yaad Dilaungi Main....
  Ye Sabko Yaad Dilaungi Main....




10) Hamein Zameen Pe Hi Aazmaalo,

      Kyunki, Taaron Ke Beech Dhundna Bahut Mushkil Hoga....

11) Khud Ko Vayang Ka Shauq Aur Kataksh Ka Ilzaam Hum Pe Aaya,

      Tarkash Tha Bhara Unka Aur Guftgoo Ka Shaq Hum Pe Aaya....

12) Zindagi Ke Ravaiye Se Uski Pehchaan Ki Yaad Aati Hai,
      Hunaar Ke Bal Koun Jiya Hai, Kismat Saath Na Hoto Aukaat Yaad Aati Hai....




13) Parda Nashin Kuch Khaas Hai Mere Liye,

      Lekin Ab Be-Aabroo Karne Mein Mazza Kuch Aur Aata Hai....

14) Shab-e-Hayaat Mein Tasveer-e-Yaar Mumkin Nahin,

      Humne To Usse Bazm-e-Junoon Mein Dekha Tha....

15) Be-Wajah Marghat Ki Shobha Badi Ja Rahi Hai,
             Aur Duniya Pata Nahin Kis Baat Pe Adday Ja Rahi Hai....
      Alp-Viraam Lag Jata Hai Yahan Pe,
             Pata Nahin Duniya Phir Bhi Kahan Bhaagay Ja Rahi Hai....




16) Fitrat Nahin Mazza Bann Gayi Hai,

      Aadat Nahin Nasha Ban Gayi Hai....

17)  Peeta Hu Uski Gurbat Ki Sharab,

                  Ke Saaki Dawa Mein Woh Baat Nahin....

18) Kismat Ke Maare Hai,
                        Varna Kissay Apne Bhi Bahut Saare Hai....


      Nabh Tak To Chu Liya Tha Humne,
                        Ke Ab Kankar Hi Apne Sahaaray Hai....


      Mrightrishna Ki To Baat Hi Na Karo Tum,
      Mrightrishna Ki To Baat Hi Na Karo Tum,
                        Humne To Singh Ko Bhi Lalkaara Hai....


      Sonay Jaisi Chamak Hoti Thi Apni,
                       Ke Aaj Khud 'Rajat' Se Haara Hai....




19) Beware!!!  GOD Is Here ....

      Sumdrishti, Sumkone Ek Nazariya Hai,

                                       Durjan, Danav Ki Ek Gathariya Hai....

    

    Tarkeeb, Taalash Ek Aavashakta Hai,

                                       Kaaba, Kailasa Ek Vakta Hai....

   Vyakyansh, Vayank Ek Alaap Hai,

                                       Kriya, Karta Ek Jeevan Ka Saar Hai...

   Tathya, Tript  Ek Parinaam Hai,

                                       Hum Mein Hi Maulaa, Mahavir , Ek Viraajmaan hai....

               
20) Dharti Kya, Humne To Suraj Ke Chakkar Kaat Liye,

                           Dhuri Pe Reh Kar Hi, Barso Maas Jhaank Liye...

      Abhi To Aasmaan Ko Chunay Ki Talab Jaari hai,

                          Wahi Soach Aaj Maine Sagar Mein Kood De Maari Hai....

     Aaj Taaron Ke Beech Se Nikal Jaunga Main,

                           Chand Ko Chunay Ki Chahat mein Tuta Hua Tara Kehlaunga Main....

21) Jhalak Bhar Leke Rakh Lunga Uski,
                 Ke Woh Shaqs Kuch Pareshaa Sa Karta Hai....


      Uske Aainay Mein Jab Dekha Apna Saaya,
                Ke Woh Shaqs Kuch Pareshaa Sa Karta Hai....


      Uski Kashish Mein Jab Phoolo Ko Bikhartay Dekha,
               Ke Woh Shaqs Kuch Pareshaa Sa Karta Hai....


      Ye Minaar, Ye Darakht , Issi Aabo-Hawa Mein Dekha Tha Ussay,
               Ke Woh Khuda Ka Aks Kuch Pareshaa Sa Karta Hai...


     Ab Bhi Uss Se Milne Ki Chahat Mein Jala Rakhi Hai Shamma,
               Ke Woh Parwana Kuch Pareshaa Sa Karta Hai.....




22) Yeh Rang, Yeh Palaash Ke Phool, Yeh Kajal Uska,

       Kal Raat Swarnim Abha Mein Bheega Tha Aanchal Jiska.....

      Yeh Shokhi, Yeh Patang, Yeh Hawa Sa Matakna Uska,

      Kal Raat Maanjay Mein Uljha Tha Imaan Jiska.....

23) Khilli Dhoop Mein Baarish Ke Tasaavur Se Inderdhanush Hota Hai,

      Khaali Baarish Mein To Sirf Gubbar Zameen Pe Gira Hota Hai.....

24) Khawahish....Tujh Se Milne Ke Baad Zindagi Ki Taaseer Badalne Lagi....
                           Tamana Ki Chashni, Justjoo Ke Saanchay Mein Dhalnay Lagi....