What does view mean in sql

SQL view is a virtual table that derives data from the base table, does not store actual data, and is dynamically generated during query. Benefits include: data abstraction, data security, performance optimization, and data integrity. Views created with the CREATE VIEW statement can be used as tables in other queries, but updating a view actually updates the underlying table.

Views in SQL

What are views?

A view is a virtual table in SQL that derives data from one or more underlying tables. It does not store actual data, but dynamically generates data when querying based on definitions.

Advantages of Views

• Data Abstraction: Views allow you to hide the complexity of the underlying tables, providing users with a simplified and consistent data view.
• Data Security: Views can be used to restrict users' access to sensitive data, allowing them to view only the information they need.
• Performance Optimization: Views can improve query performance by optimizing queries and reducing the number of accesses to the underlying tables.
• Data Integrity: Views ensure that data derived from underlying tables is always accurate and consistent.

Creation of views

Use the SQL statement CREATE VIEW to create a view. This statement specifies the name of the view, the query to derive the data, and optional column aliases.

<code class="sql">CREATE VIEW view_name AS
SELECT column1, column2
FROM table1
WHERE condition;</code>

Usage of views

Views can be used as tables in other queries. They can be retrieved, updated, deleted, and inserted as if they were actual tables. However, updates to the view will actually be reflected in the underlying table.

The difference between views and tables

• Data storage: Views do not store actual data, while tables store actual data.
• Dynamic generation: Views dynamically generate data at query time, while tables always contain their data.
• Update operation: Update operations on the view will affect the underlying table, while update operations on the table will not affect the view.

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