Informatics Practices
Answer
The Cartesian product of two tables is a relation that contains all possible concatenations of all rows of both the participating relations (tables).
The Cartesian product and joins are related because a Cartesian product, also known as a cross join, is a very basic type of join without any condition. It pairs every row from one table with every row from another, creating a complete combination of all rows. Meanwhile, a join is a query that combines rows from two or more tables based on a specified condition.
Related Questions
Assertion. 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.
Assertion. 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.
What is a join ? How is natural join different from an equi-join ?
What is a table alias ? What is the purpose of table alias ?