Database Views

Creating a Database View in SQL

Creating a database view in SQL involves defining a virtual table based on the result set of a SELECT query. This allows users to simplify complex queries and enhance data accessibility. Views can represent a subset of data or aggregate information from multiple tables.

To create a view, the SQL statement ‘CREATE VIEW’ is used followed by the view name and the SELECT statement defining the view’s contents. Understanding how to effectively create and manage views can significantly streamline database interactions.

Advantages of Database Views

Improving Data Security

In sensitive environments, views restrict user access to certain data without exposing the complete database. This allows organizations to comply with privacy regulations while allowing users to perform necessary functions.

Simplifying Complex Queries

By encapsulating complex joins and calculations, views make it easier for users to interact with data. This is particularly useful in reporting and analytics, where users can retrieve necessary insights without deep database knowledge.

Drawbacks of Database Views

Database views can introduce additional overhead, especially if they involve complex queries or join operations. This can lead to slower response times if not managed properly.

Example Database View

Suppose we have two tables: employees and departments.

Employees Table

Departments Table

SQL to create the view

We want to create a view that shows the employee’s full name and the department they work in, with the salary information.

SQL to create the view:

Result of the View

The view will provide a combined result from the employees and departments tables.

How it works:

• The view employee_department_view combines data from the employees table and the departments table.
• You can query the view like a regular table: SELECT * FROM employee_department_view;
• This simplifies the query and abstracts the complexity of joining the tables each time.