Views¶

A view is a virtual table generated from a SQL query. It allows users to simplify complex queries, hide sensitive data, and provide a customized view of the database without altering the underlying schema.

Advantages of Using Views¶

Benefits	Description
Simplification	Views simplify complex queries by encapsulating them into a single, reusable object. They provide a convenient way to abstract and hide the complexity of underlying tables.
Security	Views can enhance security by restricting access to sensitive data. Users can be granted access to views containing only the necessary columns, without direct access to the tables.
Customization	Views enable users to create customized perspectives of the data, presenting only the relevant information needed for specific tasks or reports.
Performance	Views can improve query performance by pre-computing and caching results, reducing the need to repeatedly execute complex queries.

Disadvantages of Using Views¶

Disadvantages	Description
Complexity	Views can introduce complexity to the database schema and query execution plan, making it harder to optimize and troubleshoot performance issues.
Overhead	Views may incur overhead in terms of storage and processing resources, particularly for materialized views or views involving joins and aggregation functions.
Maintenance	Views require maintenance to keep them synchronized with the underlying tables. Changes to the base tables may impact the results returned by the view.
Limited Use	Views have limitations in terms of updateability and support for certain SQL operations, such as ordering or grouping by columns not present in the underlying tables.

Create view¶

mysql> CREATE VIEW customer_orders AS
    SELECT customers.name, orders.order_id, orders.total_amount
    FROM customers
    JOIN orders ON customers.customer_id = orders.customer_id;

mysql> CREATE VIEW recent_orders AS
   SELECT *
    FROM orders
    WHERE order_date >= CURDATE() - INTERVAL 30 DAY;

Drop view¶

mysql> DROP VIEW IF EXISTS customer_orders;

mysql> DROP VIEW IF EXISTS recent_orders;

Database management¶

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Last update: 2024-09-17