[amp_mcq option1=”Union” option2=”Cartesian product” option3=”Equi Join” option4=”square ” correct=”option4″]
The correct answer is (d). Square is not an operator of relational algebra.
Relational algebra is a formal system for manipulating relations. It is a mathematical model for relational databases and provides a theoretical foundation for relational database theory.
The basic operators of relational algebra are:
- Selection (Ï): Selects tuples from a relation that satisfy a given condition.
- Projection (Ï): Projects a relation onto a subset of its attributes.
- Union (âª): Combines two relations into a new relation that contains all tuples from both relations.
- Intersection (â©): Combines two relations into a new relation that contains only the tuples that are in both relations.
- Difference (â): Combines two relations into a new relation that contains all tuples from the first relation that are not in the second relation.
- Cartesian product (Ã): Creates a new relation that contains all possible pairs of tuples from the two relations.
- Equi join (â): Creates a new relation that contains all tuples from the two relations that have matching values on a specified set of attributes.
The square operator is not an operator of relational algebra. It is a mathematical operator that is used to calculate the square of a number.