What are Views in SQL , Different Types , Syntax and Uses of Views in SQL Server

Hi, in this post I will explore the Views in SQL, Views are an important object in database

A VIEW is a virtual table that represents the data  in an alternative way

A VIEW contains queries that retrieve data as needed.

VIEWS provide a level of encapsulation.

We can create two types of view :

1)Static view

2)Dynamic view

Static View:

Also known as read-only view.

With the help of this view we can only access the information from the table but we cannot modify the information in the table.

If you are using order by clause or group by clause in the select statement while creating the view then this type of view will be static view.

Dynamic View:

Also known as updatable view.

By using dynamic view we can access the information from the table as well as we can insert update or delete the information in the table.

If we are creating a view and in the select statement you are not using the order by or group by clause then this type of view is called dynamic view.

If we want to insert the information in the table with the help of view then all the primary key column and not null column must be available in the view

Syntax

SQL command for creating a View is:

CREATE VIEW view_name

AS SQL Query

SQL command to Run a view  is:

SELECT * FROM view_name

SQL command to Drop a view is:

DROP VIEW view_name

SQL command to Modify a view is:

REPLACE VIEW view_name

AS SQL Query

Example

Create:

CREATE VIEW EmployeeView

AS SELECT First_Name,Last_Name from EmployeeMaster

Run:

SELECT * FROM  EmployeeView

Drop:

DROP VIEW EmployeeView

Modify

REPLACE VIEW view_name

AS Select First_Name from EmployeeMaster

Uses of Views

1) To reuse SQL statements.

2) To simplify complex SQL operations. After the query is written, it can be reused easily, without having to know the details of the underlying query itself. i.e. using a multi join query multiple times causes the code to be viewed complicated hence we write a view and use it, this is a form of abstraction in database

3)To expose parts of a table instead of complete tables.

4) To change data formatting and representation. Views can return data formatted and presented differently from their underlying tables.