Monday 11 March 2024
कर्म और धर्म
Thursday 7 March 2024
7 मार्च की महत्त्वपूर्ण घटनाएँ
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Sanchar Saathi Web Portal Kya hai
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Wednesday 28 February 2024
S P SHARMA SIR! Who is S P SHARMA Sir? S P SHARMA SIR kon hai
S P SHARMA SIR (Lecturer Computer Science) Age, Wife, Family, Biography & More
Full name of S P SHARMA SIR is Pandit Sachin Parashar Sharma Ji.
S P SHARMA SIR is Founder and Director of S P SHARMA CLASSES (SPSC), S P SHARMA FOUNDATION.
S P SHARMA SIR is a Computer Science Lecturer in Delhi.
S P SHARMA SIR is a prominent and knowledgeable teacher in the field of Computer Science. His concepts are clear and his practical knowledge makes it even more interesting for students to understand and relate to technical topics. Their courses, video lectures, test series, and books can help students in their studies.
S P SHARMA SIR कंप्यूटर विज्ञान के क्षेत्र में एक प्रमुख और ज्ञानवान शिक्षक हैं। उनके अवधारणाएँ स्पष्ट हैं और उनकी व्यावहारिक ज्ञान छात्रों को तकनीकी विषयों को समझने और संबंधित करने में और भी रोचक बनाता है। उनके कोर्स, वीडियो लेक्चर्स, टेस्ट सीरीज, और पुस्तकें छात्रों को उनकी पढ़ाई में मदद कर सकती हैं।
Bio/Wiki
Names:
|
S P SHARMA SIR |
Profession: |
Lecturer Computer Science |
Famous For: Books: |
His
simple and easy teaching style. Teaching Computer Science to TGT/PGT,
UGC NET Aspirants, S P SHARMA CLASSES CS CRACKER Vol - 1 and CS CRACKER Vol - 2
|
Physical Stats & More
Height
(approx.) in centimetres : |
175 cm |
in meters : |
1.75 m |
in feet
& inches : |
5’ 9” |
Eye Colour
: |
Black |
Hair Colour
: |
Black |
Personal Life
Date of Birth |
19 Dec 1987 |
Age (as of 2024) |
36 Yrs |
Birthplace |
Khatauli,
Uttar Pradesh |
Nationality |
Indian |
Hometown |
Bhayangi,
Post – Khatauli, Distt. Muzaffarnagar, Uttar Pradesh |
School |
Govt.
Primary School Bhayangi, Adarsh Janta Inter College Bhangela, JLNS Inter
College Khatauli,
|
College/University |
K.K. Jain
P.G. College Khatauli (CCS University), Uttrakhand Technical University
Dehradun, CRSU Jind Haryana |
Educational
Qualification(s) |
B.Sc. (PCM), MCA, M.Tech.
(IT), B.Ed., ‘O’ Level, ‘A’ Level |
Govt. Exam Written Qualified |
CTET, U P
Police Computer Operator, UGC NET DSSSB PGT
Computer Science, KVS PGT Computer Science, Army Public School PGT CS |
Religion/Religious Views |
He follows Hinduism. He is
devotee of Lord Shiva, Krishna and Rama
|
Relationships & More
Marital Status : |
Married |
Family
Wife/Spouse: |
Rita Sharma
(House Wife) |
Children: |
Daughter:
Saanvi
Parashar Sharma Son: Shiva Parashar Sharma |
Parents: |
Father: Sh. Vinod Kumar Sharma
(Farmer) Mother: Late Mrs. Usha Sharma
(House Wife) |
Siblings
: |
S P SHARMA
SIR has a brother and a sister. His brother name is Mohit Sharma |
Favorites
Food : |
Curry Chawal |
Beverage : |
Milk |
Holiday
Destination: |
Vrindavan
or any Spritual place |
Film(s) : |
Thriller and
Comedy |
Actor: |
Shahrukh
Khan, Sunny Deol |
Game : |
Cricket
(Outdoor), Ludo (Indoor) |
Player : |
Sachin
Tendulkar, Rohit Sharma, Virat Kohli |
Color : |
Yellow |
Some Lesser Known Facts About S P SHARMA SIR
- S P SHARMA SIR is the founder and director of S P SHARMA CLASSES - SPSC an Authentic Platform for learners of Computer Science.
- S P SHARMA SIR grew up in a poor brahman family in a small village Bhayangi in Muzaffarnagar, Uttar Pradesh.
- S P SHARMA SIR father is a farmer and his mother was a house wife.
- He completed his schooling from the Govt. Primary school of his village.
- In his childhood, his favorite subject was Mathematics, but he was poor in English and other subjects. When he was in 9th class he stared coaching class in his village.
- He want to became a mathematics teacher since childhood. So When he was in 11th class, he started mathematics coaching and continue is coaching with his study.
- He passed his Bachelor in Science (B.Sc.) in Mathematics, Physics and Chemistry.
Tuesday 20 February 2024
Projection and Selection Practice Questions in relational algebra
Projection and Selection Practice Questions:
Student
S_ID |
NAME |
Branch |
1 |
A |
CS |
2 |
B |
IT |
3 |
C |
CS |
4 |
D |
CS |
5 |
E |
EE |
6 |
F |
EC |
7 |
G |
EE |
- Find the names of all students from CS branch.
Π name (σ Branch = ‘CS’ (Student))
Account (account_no, branch_name, balance)
- Find those account numbers where balance is less than 1000.
Π account_no (σ balance<1000 (Account))
Loan(loan_no, branch_name, amount)
- Find those loan numbers which are from Delhi branch with amount greater than 1000.
Π loan_no (σ branch_name=’Delhi’ ^ amount>1000 (Loan))
Branch (Branch_name, Branch_city, assets)
- Find branch_name and branch_city with assets more than 100000.
Π branch_name , branch_city (σ assets>100000 (Branch))
Projection Operator in Relational Algebra
Projection Operator-
- Projection Operator (π) is a unary operator in relational algebra that performs a projection operation.
- It displays the columns of a relation or table based on the specified attributes.
- It is a fundamental / Basic operator
- It is a unary operator
Syntax-
π<attribute list>(R) |
Example-
Consider the following Student relation-
ID | Name | Subject | Age |
100 | Ashish | Maths | 19 |
200 | Rahul | Science | 20 |
300 | Naina | Physics | 20 |
400 | Sameer | Chemistry | 21 |
Student
Result for Query πName, Age(Student)-
Name | Age |
Ashish | 19 |
Rahul | 20 |
Naina | 20 |
Sameer | 21 |
Result for Query πID , Name(Student)-
ID | Name |
100 | Ashish |
200 | Rahul |
300 | Naina |
400 | Sameer |
Important Points-
Point-01:
- The degree of output relation (number of columns present) is equal to the number of attributes mentioned in the attribute list.
Point-02:
- Projection operator automatically removes all the duplicates while projecting the output relation.
- So, cardinality of the original relation and output relation may or may not be same.
- If there are no duplicates in the original relation, then the cardinality will remain same otherwise it will surely reduce.
Point-03:
- If attribute list is a super key on relation R, then we will always get the same number of tuples in the output relation.
- This is because then there will be no duplicates to filter.
Point-04:
- Projection operator does not obey commutative property i.e.
π <list2> (π <list1> (R)) ≠ π <list1> (π <list2> (R))
Point-05:
- Selection Operator performs horizontal partitioning of the relation.
- Projection operator performs vertical partitioning of the relation.
Point-06:
- There is only one difference between projection operator of relational algebra and SELECT operation of SQL.
- Projection operator does not allow duplicates while SELECT operation allows duplicates.
- To avoid duplicates in SQL, we use “distinct” keyword and write SELECT distinct.
- Thus, projection operator of relational algebra is equivalent to SELECT operation of SQL.
Selection Operator in Relational Algebra
Selection
Operator-
·
Selection Operator (σ) is a unary operator in relational
algebra that performs a selection operation.
·
It selects those rows or tuples from the relation that
satisfies the selection condition.
·
It is a fundamentals / Basic operator
·
It is a Unary Operator
σ<selection_condition>(R)
·
Select tuples from a relation “Books” where subject is
“database”
σsubject = “database” (Books)
·
Select tuples from a relation “Books” where subject is
“database” and price is “450”
σsubject = “database” ∧ price = “450” (Books)
·
Select tuples
from a relation “Books” where subject is “database” and
price is “450” or have a publication year after 2010
σsubject = “database” ∧ price =
“450” ∨
year >”2010″ (Books)
Important
Points-
Point-01:
·
We may use logical operators like ∧ , ∨ , ! and relational operators
like = , ≠ , > , < , <= , >= with the selection
condition.
Point-02:
·
Selection operator only selects the required tuples
according to the selection condition.
·
It does not display the selected tuples.
·
To display the selected tuples, projection operator is
used.
Point-03:
·
Selection operator always selects the entire tuple. It
can not select a section or part of a tuple.
Point-04:
·
Selection operator is commutative in nature i.e.
σ A ∧ B (R)
= σ B ∧ A (R)
OR
σ B (σ A(R))
= σ A (σ B(R))
Point-05:
·
Degree of the relation from a selection operation is same
as degree of the input relation.
Point-06:
· The number of rows returned by a selection operation is obviously less than or equal to the number of rows in the original table.
·
Minimum Cardinality = 0
·
Maximum Cardinality = |R|
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