Reg algebra girija-projection
15
R1 := π L (R2) L is a list of attributes from the schema of R2. R1 is constructed by looking at each tuple of R2, extracting the attributes on list L, in the order specified, and creating from those components a tuple for R1. Eliminate duplicate tuples, if any. PROJECTION
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Transcript of Reg algebra girija-projection
R1 := πL (R2)
L is a list of attributes from the schema of R2.
R1 is constructed by looking at each tuple of R2, extracting the attributes on list L, in the order specified, and creating from those components a tuple for R1.
Eliminate duplicate tuples, if any.
PROJECTION
2
Example: Projection
milk milk_type price Al-marai Full_Fat 2.50 Al-marai Refresh 2.75 Lancor Full_Fat 2.50 Lancor Refresh 3.00
Prices := πmilk,price(Sells):
milk price Al-marai 2.50 Al-marai 2.75 Lancor 2.50 Lancor 3.00
Sells
Display the name column only Display name column whose salary is greater than 80000
Projection – exercise 1
Projection – exercise 1 solution
PROJECTION-exercise 2 solution
PROJECTION-exercise 3
Display Surname,Firstname Display Department,head
PROJECTION-exercise 3 solution
PROJECTION-exercise 4
Display all the Acc-no, title of the book
PROJECTION-exercise 4 Solution
PROJECTION-exercise 5
Display name, dept of the EMP
PROJECTION-exercise 5 Solution
Display age, weight from person
PROJECTION-exercise 6
PROJECTION-exercise 6 solution
