Question

Data stored in separate tables can be reconstructed through the use of ____________________.

a) Cartesian joins
b) Subqueries
c) Indexing
d) Joins

Answer 1

Data from separate tables is combined using joins, which match rows based on related columns. Joins come in several types like inner join, left join, right join, and full outer join, each with a specific use case.

Step-by-step explanation:

Data stored in separate tables can be reconstructed through the use of joins. In the context of relational databases, a join is a SQL operation used to combine rows from two or more tables based on a related column between them. There are several types of joins, including inner join, left join, right join, and full outer join, each serving a specific purpose to achieve the desired result set.

For example, if one table contains user information and another contains user orders, a join can be used to match each order with the specific user details. An inner join would return only the records where a match is found in both tables, while a left join would return all records from the left table (user information), and the matched records from the right table (user orders), plus null for any non-matching records.