Join Expressions

Question 1
Marks : +2 | -2
Pass Ratio : 100%
What is the function of inner join?
It preserves tuples only in the relation named before the operation
It preserves tuples only in the relation named after the operation
It preserved tuples in the relations named on both the sides of the operation
It does not preserve any tuples on either side of the relation
Explanation:
The join operations that do not retain mismatched tuples are called as inner join operations. The inner join operation does not preserve any tuples on either side of the relation.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
State true or false: on and where behave differently for outer join
True
False
Explanation:
The on condition is a part of the outer join syntax but the where clause isn’t.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
What is the function of a full outer join?
It preserves tuples only in the relation named before the operation
It preserves tuples only in the relation named after the operation
It preserved tuples in the relations named on both the sides of the operation
It does not preserve any tuples on either side of the relation
Explanation:
The full outer join operation preserves the tuples named on both the sides of the operation. Unlike the inner join, outer joins preserve tuples from either or both sides of the operation.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
What is the function of a left outer join?
It preserves tuples only in the relation named before the operation
It preserves tuples only in the relation named after the operation
It preserved tuples in the relations named on both the sides of the operation
It does not preserve any tuples on either side of the relation
Explanation:
The left outer join operation preserves the tuples named before the operation.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
The join operations that do not retain mismatched tuples are called as _________ operations
outer join
natural join
full outer join
inner join
Explanation:
The join operations that do not retain mismatched tuples are called as inner join operations. The inner join operations do not preserve any tuples that are otherwise preserved in the outer join operation.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
What is the function of a right outer join?
It preserves tuples only in the relation named before the operation
It preserves tuples only in the relation named after the operation
It preserved tuples in the relations named on both the sides of the operation
It does not preserve any tuples on either side of the relation
Explanation:
The right outer join operation preserves the tuples named after the operation.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
If a left outer join is performed and the tuple on the left hand side does not match with the tuple on the right hand side, what happens to the values that are preserved on the left hand side?
They are given null values
They are given a random value
The user is asked to enter data
The query is declared invalid by the compiler
Explanation:
If a left outer join is performed and the tuple on the left hand side does not match with the tuple on the right hand side, the remaining values are given a null value.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
What is the difference between a join and an outer join operation?
There is no difference
Join preserves a few tuples that are otherwise lost in the outer join
Outer join preserves a few tuples that are otherwise lost in the join
An outer join can be used only on outer queries whereas a join operation can be used in Subqueries
Explanation:
The outer join operation preserves a few tuples that are otherwise lost in the join operation. The outer join operation preserves the tuples to the right of the operation.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
The on condition appears at the _______ of the join expression
Beginning
End
Between
The on condition is not related to join expression
Explanation:
The on condition appears at the end of the join expression. Because it states the condition that the relations under the join operations get matched based on.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Which off the following is not a valid type of join?
left outer join
outer join
join
full join
Explanation:
There is no such join called as full join. There is a full outer join but a full join does not exist.