Database Key


Today one new label is added. "Database". There are set of articles planned in this category. Today is the first one. 

Most of us know, in RDBMS, database table has primary key and foreign key. Any idea about other types of key? Below tables describes all database keys and relations among them. 



Primary
Unique
Surrogate
Foreign
Composite
Simple
1
Primary
1
1
May be
May be
May be
May be
2
Unique
May be
1
May be
May be
May be
May be
3
Surrogate
May be
1
1
May be
0
1
4
Foreign
0
May be
0
1
May be
May be
5
Composite
May be
May be
0
May be
1
0
6
Simple
May be
May be
0
May be
0
1
7
Super
0
1
0
0
May be
May be
8
Minimal super
May be
1
0
0
May be
May be
9
Tirival Super
May be
1
0
May be
1
0
10
Candidate
May be
1
May be
May be
May be
May be
11
Alternate
0
1
1
May be
May be
May be
12
Natural
May be
1
0
May be
1


Super Minaml super Tirival Super Candidate Alternate Natural
1 Primary May be May be 0 1 0 May be
2 Unique 1 May be May be 1 May be May be
3 Surrogate 0 0 0 May be May be 0
4 Foreign May be May be 0 0 0 0
5 Composite May be May be 1 1 May be 0
6 Simple 0 May be 0 May be May be May be
7 Super 1 May be 1 0 0
8 Minimal super 1 1 0 1 May be May be
9 Tirival Super 1 0 1 1 May be 0
10 Candidate 1 1 1 1 May be May be
11 Alternate 1 1 0 1 1 May be
12 Natural 0 1 May be 1



The above table should be read, row wise

For example 1st row: 

Is primary key is unique? 1 = Yes
Is it surrogate? The surrogate key can become primary key. However the primary key is not always surrogate. So answer "May be"
and so on. Here 1 = Yes and 0 = No

Here are some key points about database keys
  • The primary key cannot be NULL
  • The unique key can be NULL
  • The primary key is always unique
  • All unique keys are candidate key to become primary key
  • Primary key can be one of the candidate key or it can be surrogate key
  • The candidate key, who is not primary key is alternate key. 
  • If surrogate key is primary key, then all candidate keys are alternate keys. 
  • Simple key and composite key are mutually exclusive. 
  • The compound key should have at least two simple keys
  • The composite key is extension of compound key
  • Natural key and domain key are synonyms.
  • Composite key, compound key, aggregate key and concatenated key. All are in a way same. 
  • Minimal super key and candidate key are in a way same. 
  • Trivial super key means all columns.   
Stay tune to this blog "Express YourSelf !" for more interesting articles. 

Internet of Things


I have posted few mindmaps on this blog: IPSec , IMS and SIP, ANDSF

Today one more. It is about IoT. "Internet of Things" is a buzzword. In fact, IoT and 5G are like two sides of single coin. There are many standards related to IoT defined by various standarisation bodies. These standards are for wired connection and wireless connection. The wireless connection is also referred as Low Power Wide Area Network (LP-WAN). It is further categorizes licensed spectrum and Non-licensed spectrum. IoT is also about many protocols used. The IoT application uses database with specific set of features.


  

As per Wikipedia

A mind map is a diagram used to visually organize information. A mind map is hierarchical and shows relationships among pieces of the whole.[1] It is often created around a single concept, drawn as an image in the center of a blank page, to which associated representations of ideas such as images, words and parts of words are added. Major ideas are connected directly to the central concept, and other ideas branch out from those.

Diwali Rangoli


Rangoli one of the most popular art forms in India. It is a form of sandpainting decoration that uses finely ground white powder and colors, and is used commonly outside homes in India.

I observed that @ South India daily people decorate the entrance with white powder Rangoli. @
my origin, Gujarat state, during Diwali festival, we all prepared colorful Rangolis at our entrance. It is welcoming to goddess of wealth - Lakshami.

At my native place Mithapur, we have competition for preparing the best Rangoli during Diwali festival. Today let me share photographs of last year Diwali 2015. You may also like previous article: http://layers7.blogspot.in/2008/11/rangoli-one-of-most-popular-art-forms.htmlhttp://layers7.blogspot.in/2008/11/rangoli-one-of-most-popular-art-forms.html



Semiconductor Industry 2015




Rank Company % Share USD B Up/Down Location
10 STMicroelectronics 2 6.8 -7.8 Geneva, Switzerland
9 Infineon Technologies 2 6.8 19.6 Germany
8 Broadcom 2.5 8.3 Irvine, Calif
7 Toshiba 2.7 9.1 -14.1 Japan
6 Texas Intruments 3.4 11.5 0 Dallas
5 Micron Technology 4.1 13.8 -15.1
4 Qualcomm 4.8 16 -16.7 San Diego
5 SK Hynix 4.9 16.3 2.4 S Korea
6 Samsung 11.3 37.8 9 S Korea
1 Intel 15.4 51.7 -1.2 Santa Clara, Calif
0 Misc 46.9 161.9
100 340




Ref: http://www.crn.com/slide-shows/components-peripherals/300080346/gartner-10-semiconductor-vendors-with-the-most-market-share-in-2015.htm

My Poems


Let me introduce my other blog name "My Poems". As name suggest it contains all my poems. Today I want to write a brief article about my poems. I wrote earlier about it, however those hyper links are broken now. 

My all poems related articles are hereI wrote my first poem about Diwali wishes. I also captured it in my blog. Nena Pidheya Modhala Kavana? After that, HDH Pramukh Swami Maharaj inspired me to write many other subsequent poems. All those poems are here I also wrote about all my romantic poems, "open source love letter" etc. here :  Valentine's Day : Poems

I write many poems in college days. I never wanted to become a poet, who recite boring poems in poets' meet (KAVI SAMELAN). I always tried to write some interesting poems, that have potential to become popular. They looks like immature, however the audience should like them. I recited two such poem about our college life in college events. They both became super hit. Still my seniors and juniors remembered me for those poems. They are CHITKAAR (shouting in pain) and SIGMA (summation) 

I wanted to write a book about my poems. Now today in Facebook era, no one read books. I slowly keep uploading all my poem on blog. Today I completed. they all are here. My Poems I can keep on writing about all poems. Then this article will be long and boring. So let me list out the categories of poems. The reader can choose as per his/her interest. Off course many poems belongs to multiple categories.  Here is the list in alphabetical order


  • College Life
  • Gazal You may feel that some of them does not looks like Gazal !!!
  • HDH Pramukh Swami Maharaj Some of these poems are recited in front of Param Pujya Swamiji. 
  • Most of the poems are in Gujarati language. Few are in Hindi
  • Humorous 
  • Inspirational
  • About Nature
  • Romantic
  • Sonet You may feel that some of them does not looks like Sonet!!!
  • Spiritual My majority poems got this tag. They contains practical wisdom of living life in present moment. "AB" and "HAVE" (meaning now) capture the thought process of mind after doing my first advance meditation course with Guruji


I wrote poems on many subjects. Some of them won prizes in competitions. Some of them published in SHREE magazine. One was broadcasted on FM Radio DIN HUVA Begin...! However there are few poems, I liked the most. They are (1) Ekaanki (a drama with one part) This describe MUMUKSHATAA (desire to meet God) (2) Shabari. She is a famous character of Ramayana epic. 

i wrote about nice poems in Bollywood songs. That article become very popular. I also upload breathless song.  

So I hope, some of the poems you may like. Stay tune to this blog Express YourSelf !