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Explanation

A View in a database is a virtual table created from a SQL query. It does not store data separately. Instead, it shows data from one or more tables whenever the view is queried.

Code:

CREATE VIEW employee_view AS SELECT id, 
name, salary FROM employees;

Explanation

Views help simplify complex queries. Instead of writing long JOIN queries repeatedly, developers can query the view directly.

Code:

SELECT * FROM employee_view;

Explanation

Views can improve security by exposing only selected columns to users while hiding sensitive data.

Code:

CREATE VIEW public_employee_view AS 
SELECT id, name FROM employees;

Explanation

Views can combine data from multiple tables using JOIN operations.

Code:

CREATE VIEW employee_department_view 
AS SELECT e.name, d.department_name 
FROM employees e JOIN departments d 
ON e.department_id = d.id;

Explanation

Updating data through a view is possible in some databases if the view is simple and based on a single table.

Code:

UPDATE employee_view SET salary = 
50000 WHERE id = 1;

Explanation

Views do not physically store data like tables. Every time the view is accessed, the database executes the underlying SQL query.

Code:

SELECT * FROM employee_view;

Explanation

Materialized Views are special views that store data physically for faster performance.

Code:

CREATE MATERIALIZED VIEW sales_summary
 AS SELECT product_id, SUM(amount) AS 
total_sales FROM sales GROUP BY product_id;

Explanation

Views can be deleted when no longer needed.

Code:

DROP VIEW employee_view;