Which of the following relational algebra commands or combination of commands is capable of retrieving one or more columns of a relation?
A) Select.
B) Project.
C) Join.
D) Select and Project.
E) Select, Project, and Join.

Question

Quizplus · Accepted Answer

The Project command is used to retrieve one or more columns from a relation. Select is used to retrieve specific rows based on a specified condition, Join is used to combine two relations based on a common attribute, and Select and Project can be combined to retrieve specific rows and columns from a relation. However, Select, Project, and Join together are not necessary to retrieve columns from a relation.

Which of the Following Relational Algebra Commands or Combination of Commands