Database - SQL for Database Construction - Discussion

SQL View is a virtual table based on the result set of an SQL query.

It does not store physical data itself; instead, it dynamically queries the underlying tables whenever called. Views serve several practical purposes in database design and security:

To hide columns (Column-Level Security): You can grant a user access to a view that selects only specific columns (e.g., employee_id, name) while omitting sensitive columns (e.g., salary, ssn) from the base table.

To hide rows (Row-Level Security): By adding a WHERE clause to the view's definition (e.g., WHERE department = 'Sales'), you restrict users to viewing only the rows they are authorised to see.

To hide complicated SQL statements (Abstraction & Simplification): Complex joins, aggregations, subqueries, or business logic can be packaged into a single view.

Users can then query the view with a simple SELECT * FROM view_name; without needing to write or understand the complex underlying query.