π <list1> (π <list2>)(R)) =π<list1>(R) as long as <list2> contains the attributes in <list1>
Anonymous Quiz
86%
T
14%
F
The Cardinality of the relation resulting from a Project operation is …........... the cardinality of R.
Anonymous Quiz
5%
<
18%
=
4%
>
73%
<=
Which Relational algebra expression is correspond to the following SQL query:
Anonymous Quiz
31%
σDno=4 AND Salary>25000 (EMPLOYEE)
11%
σDno=4 (σ Salary>25000 (EMPLOYEE)
48%
π name (σDno=4 (σ Salary>25000 (EMPLOYEE)))
10%
σDno=4 and Salary>25000 (π name(EMPLOYEE))
The result of the ……….operation can be visualized as a vertical partition of the relation into two relations.
Anonymous Quiz
8%
Select
73%
Project
13%
Join
5%
Cartesian Product
σ<cond1>(σ<cond2>(σ<cond3>(R))) is equivalent to
Anonymous Quiz
4%
σ<cond3> AND <cond1> AND <cond2>(R)
7%
σ<cond1> AND <cond3> AND <cond2>(R)
5%
σ<cond2> AND <cond1> AND <cond3>(R)
85%
All the above
RENAME operation which can rename either the relation name or the attribute names, or both is a unary operator
Anonymous Quiz
94%
T
6%
F
ρ(B1, B2, ..., Bn)(R)
Anonymous Quiz
5%
renames the relation only
70%
renames the attributes only.
24%
renames both the relation and its attributes
ρS(B1, B2, ..., Bn)(R)
Anonymous Quiz
3%
renames the relation only
5%
renames the attributes only.
92%
renames both the relation and its attributes,
Relational set operators are used to combine or subtract the records from two tables
Anonymous Quiz
95%
T
5%
F
RELATIONAL SET OPERATORS are used for doing set operations on relations having same schema.
Anonymous Quiz
96%
T
4%
F
...... , is a relation that includes all tuples that are either in R or in S or in both R and S. Duplicate tuples are eliminated
Anonymous Quiz
92%
UNION
6%
INTERSECTION
2%
MINUS
In order to set operators to work in database, it should have same number of columns participating in the query and the datatypes of respective columns should be same is called Union Compatibility.
Anonymous Quiz
93%
T
7%
F