Databases & Data Storage
View
Definition
In database theory, a view is the result set of a stored query on the data, which the database users can query just as they would in a persistent database collection object. This pre-established query can be used to simplify complex queries or to restrict access to data.
Why It Matters
Views provide a layer of abstraction over the underlying tables. They can simplify complex queries for end-users and provide a security mechanism by only showing certain columns or rows from a table.
Contextual Example
A database has `Employees` and `Salaries` tables. A view called `EmployeeDirectory` could be created that joins these tables but only exposes the `EmployeeName` and `Department` columns, hiding the sensitive `Salary` information.
Common Misunderstandings
- A view does not store data itself; it is a virtual table defined by a query.
- Some databases support "materialized views," which do store the result of the query physically and are updated periodically.