Number-Systems
August 9, 2024Computer-Networks
August 9, 2024Database-Management-System
| Question 872 |
Which operation is used to extract specific columns from a table?
| Project | |
| Join | |
| Extract | |
| Substitute |
Question 872 Explanation:
Projection (π)
Projection is used to project required column data from a relation. By Default projection removes duplicate data.
Example :
R(A B C)
———-
1 2 4
2 2 3
3 2 3
4 3 4
π (BC)
B C
—–
2 4
2 3
3 4
Projection is used to project required column data from a relation. By Default projection removes duplicate data.
Example :
R(A B C)
———-
1 2 4
2 2 3
3 2 3
4 3 4
π (BC)
B C
—–
2 4
2 3
3 4
Correct Answer: A
Question 872 Explanation:
Projection (π)
Projection is used to project required column data from a relation. By Default projection removes duplicate data.
Example :
R(A B C)
———-
1 2 4
2 2 3
3 2 3
4 3 4
π (BC)
B C
—–
2 4
2 3
3 4
Projection is used to project required column data from a relation. By Default projection removes duplicate data.
Example :
R(A B C)
———-
1 2 4
2 2 3
3 2 3
4 3 4
π (BC)
B C
—–
2 4
2 3
3 4
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