Question 1

Question 1Assertion. Cartesian product and joins are related.Reason. Cartesian product is a join without any condition.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.ExplanationThe Cartesian product and joins are related because a Cartesian product is a join without any condition. While a join is a query that combines rows from two or more tables based on a specified condition, a Cartesian product (or cross join) pairs every row from one table with every row from another, resulting in a set that includes all possible combinations of rows.

Question 2

Question 2Assertion. The cardinality of a cartesian product can be predetermined, unlike joins.Reason. The cardinality of a cartesian product is cardinality of table 1 x cardinality of table 2.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.ExplanationThe cardinality of a Cartesian product can be predetermined because it is the product of the cardinalities of the two participating tables, i.e., n1 * n2 where n1 and n2 are cardinalities of the two participating tables. This is unlike joins, where the cardinality depends on the specific conditions used to match the rows from the involved tables.

Question 3

Question 3Assertion. There must be some identical columns in tables in order to get cartesian product.Reason. The cartesian product returns all possible combinations of rows from the participating tables.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is false but R is true.ExplanationThe cartesian product does not require any identical columns, it pairs each row from one table with every row from another table, creating all possible combinations of rows and returning them.

Question 4

Question 4Assertion. The join in which columns are compared for equality, is called an Equi-join.Reason. The join condition can only compare columns with equal sign.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is true but R is false.ExplanationIn an equi-join, the values in the columns being joined are compared for equality. The join condition can use various types of comparisons, including equality (=) and other logical operators such as "<>", "<", ">", "<=", ">=".

Question 5

Question 5Assertion. The join, in which columns are compared for equality, is called an Equi-join.Reason. In non-equi joins, the columns are compared with non-equality conditional operators.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true but R is not the correct explanation of A.ExplanationThe join in which columns are compared for equality is called an Equi-join. A non-equi-join involves comparing columns with non-equality conditional operators, such as '<>', '<', '>', '<=', and '>=', to specify relationships other than equality between the columns.

Question 6

Question 6Assertion. There can be joins where all records from one of tables appear irrespective of their matching rows in the other table.Reason. In LEFT JOIN, all rows from the left table appear in the result along with matching rows from the right table and NULL for the non-matching rows ; and same for the RIGHT JOIN where all rows came from the right table appear, along with only matching rows from the left table.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.ExplanationIn certain types of joins, such as LEFT JOIN and RIGHT JOIN, all records from one table appear in the result set regardless of whether they have matching rows in the other table. In a LEFT JOIN, all rows from the left table are included along with matching rows from the right table and NULL values for non-matching rows in the right table. Similarly, in a RIGHT JOIN, all rows from the right table are included along with matching rows from the left table and NULL values for non-matching rows in the left table.

Question 7

Question 7Assertion. The UNION clause combines the rows of the participating tables, removing the duplicate rows.Reason. To retain the duplicate rows in a UNION query, UNION ALL is used.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.ExplanationThe UNION clause combines the rows of the participating tables, removing duplicate rows from the final output. On the other hand, UNION ALL retains all duplicate rows from the tables in the final output.

Question 8

Question 8Assertion. The MINUS and INTERSECT operators are similar.Reason. The MINUS operator returns only the rows from the first result set while INTERSECT returns the common rows of both the result sets.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is false but R is true.ExplanationThe MINUS operator returns the rows that are only in the first result set but not in the second, while the INTERSECT operator returns all rows that are in both result sets. Hence, the MINUS and INTERSECT operators are different.

Question 9

Question 1What is unrestricted join ?

Accepted Answer

The unrestricted join of two tables is a relation that contains all possible concatenations of all rows of both the participating relations (tables).

Question 10

Question 2What is join ?

Accepted Answer

A join is a query that combines rows from two or more tables based on a condition.

Question 11

Question 3How is equi-join different from non-equi-join?

Accepted Answer

In an equi-join, the values in the columns being joined are compared for equality using the "=" operator, and all columns from the joined tables are included in the result set, even if they are identical. On the other hand, a non-equi-join specifies a relationship other than equality between the columns using operators like <, >, <=, >=, !=, or <>.

Question 12

Question 4What set operations can you perform through SQL ?

Accepted Answer

In SQL, set operations include UNION, INTERSECTION, and MINUS to combine the rows from two or more tables.

Question 13

Question 5How is UNION different from UNION ALL ?

Accepted Answer

In SQL, UNION ALL retains all duplicate rows from tables in the final output, while UNION removes duplicate rows from the final output.

Question 14

Question 6How is INTERSECT different from MINUS operation ?

Accepted Answer

In SQL, the INTERSECT operator returns rows common to two tables, while the MINUS (EXCEPT) operator retrieves unique rows from the first table that are not in the second table.

Question 15

Question 1An SQL join clause combines records from two or more tables in a database.

Accepted Answer