Informatics Practices
Assertion. 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.
SQL Joins & Grouping
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Answer
Both A and R are true and R is the correct explanation of A.
Explanation
The 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.
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Related Questions
UNION and UNION ALL produce similar results.
Assertion. 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.
Assertion. 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.
Assertion. 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.