Programs

A join is used to combine data from two or more tables based on a common column or set of columns. There are several types of joins in SQL, including inner join, left join, right join, and full outer join.Read more

A transaction is a set of SQL statements that are executed as a single unit of work. It allows multiple changes to be made to the database in a way that ensures data integrity.

A subquery is a query that is nested inside another query. It is used to retrieve data that will be used in the main query. When students first learn SQL, they often write simple queries that ask the database ...Read more

A foreign key is a column or set of columns in a table that refers to the primary key of another table. It is used to establish a relationship between two tables.When we study databases, one important idea is ...Read more

A view is a virtual table that is created based on the result of a query. It allows users to see a subset of the data in a table without actually modifying the data. Before understanding a view, it ...Read more