Set operations can be applied on any two relations with the same number of attributes.Question 3Select one:TrueFalse

A key of a relation may have more than one attribute. True False

The elements of the domain of an attribute may be ordered pairs of values. True False0.5 pointsSome relations may not have a foreign key. True False0.5 pointsA foreign key in a relation should consist of exactly one attribute. True False0.5 pointsA foreign key in a relation R can NOT be used to refer to tuples in R itself. True False

For each attribute of a relation, there is a set of permitted values, called the _______ of the attribute

Which of the following is wrong about domains of a relation?Question 29Select one:a.Two or more attributes can be defined on the same domainb.Two attributes that include values from different domains can easily be comparedc.A tuple can draw values from different domainsd.A pool of atomic values constitutes a domain

All relational operators always take one relation as the input and output another relation.Question 2Select one:TrueFalse